Organometallics 1988, 7, 883-892
= 11.3 Hz,Jp-2 = 4.8 Hz,5 1 2 = 1.4 Hz,5 1 3 = 9.8 Hz,5 2 3 = 6.2 Hz,534 = 10.2 Hz,545 = 10.2 Hz,557 = 10.2 Hz,J B = 16.9 Hz, (367 = 1.8 Hz. 13C('H} NMR (100.6M H z , benzene-de): 6 20.5 (d, PCH3,Jpc = 31 Hz), 20.8 (d, PCH;, J p c = 32 Hz), 33.4 (d, CH'H', Jpc = 13 Hz),69.0,63.1 (s, s, CH3+ CH4),91.6 (s, C5H5),111.4
(s, CHeH7), 127.8-131.4 (PCsH5,overlapping with benzene-d6 resonances), 139.4 (s, CH5),248.4 (d, CO,J p c = 28 Hz). Method B. This complex was also prepared by irradiation of 8 and PMezPh in ether at -20 "C for 5 h, followed by purification by column chromatography;the yield was 43%. (j)Synthesis of C ~ M O ( C O ) [ P ( C ~ H ~ -$pentadienyl) )~](S~~ (13). Method A. This complex was prepared similarly by irradiation of 4 in ether at -20 "C. The yield is 52%. Anal. Calcd for Cl7HZ7MoOP:C,54.55;H,7.22. Found: C,54.68;H,7.54. Mass spectrum (12eV, 98Mo,23.78%, mle): 376 (M'), 348 (M' - CO),258 (M+-PEt3).IR (Nujol): exo isomer, v(C0) 1835 cm-'; endo isomer, 1841 cm-'; v(C=C) 1617 cm-'. 'H NMR (400.1M H z , benzene-de): exo isomer, 6 -0.04 (ddd, 1 H,HI), 0.67 (m, 9 H, PCH2CH3),1.12 (m, 3 H,PCHH'-CH3),1.16 (m, 3 H,PCHH'CH,), 1.84 (ddd, 1 H,H2), 2.43 (t, 1 H,H4),3.87 (td, 1 H,H3), 4.64 (d, 5 H,C5H5),4.84 (dd, 1 H,H'), 5.52 (dd, 1 H,H6), 5.85 (dt, 1 H,H5), Jp-1 = 11.7 Hz, Jp-2 = 4.4 Hz, 5 ~ = 1.2 4 Hz, ~512 ~ = 1.4 Hz, 5 1 3 = 10.2 Hz, 5 2 3 = 6.5 Hz, 534 = 5 4 5 = 10.2 Hz, 556 = 16.8 Hz, 557 = 10.2 Hz, J67= 1.4 Hz; endo isomer, 6 0.79 (m, 9 H,PCH2CH3), 1.28 (m, 3 H,PCHH?,1.40 (m, 3 H,PCHH'), 3.80 (td, 1.53 (dd, 1 H,H'), 1.65 (d, 1 H,H2),2.77 (dd, 1 H,H4), 'H,H3),4.63 (s, 5 H,C5H5), 4.80 (dd, 1 H,H7), 5.00 (dd, 1 H), 6.78 (dt, 1 H,H5),J p 1 = 13.5 Hz, 5 2 3 = 6.0Hz, 5 1 3 = 10.7 Hz, 534 = 10.7 Hz, 5 4 5 = 10.3 HZ, 5 5 6 = 16.8 H Z , 5 5 7 = 10.2 HZ,5 6 7 = 1.0 Hz. 13C('HNMR ) (100.1M H z ,benzene-de): exo isomer, 6 8.3 (d, PCHZCH,,J p c = 18 Hz), 21.26 (d, PCH2CH3,J p c = 23 Hz),30.0 (d, CH'H', J p c = 14 Hz),63.0,67.9 (s, 9, CH2+ CH3), 91.2 (s, C5H5),108.8 (s,CH6H7), 141.5 (s, CH5),249.7 (d, CO,J p c = 38.2 Hz); endo isomer, 6 8.4(d, PCH2CH3, Jpc= 18 Hz),23.3 (d, PCH2), 33.5 (d, CH1H2, Jpc= 8 Hz), 56.2,82.6 (s, s, CH3+ CH4),89.4
883
(9,C5H5),105.5 (s, CH'H'), 145.6 (9, CH5),252.6 (d, CO,J p c 26 Hz). Method B. This complex was also prepared by irradiation of 8 and P(CH2CH3)3in ether at -20 "C for 5 h, followed by purification through column chromatography; the yield was 46%. (k)Synthesis of CpMo(C0)(PMe,) (syn -$-pentadienyl) (14). This complex was prepared similarly by irradiation of an ether solution of 8 and PMe3.The yield was 34%. Anal. Calcd C,50.61;H,6.32. Found: C,50.94;H,6.48. for Cl4HZ1MoOP: IR (pentane): v(C0) 1832 cm-I; v(C=C) 1617 (w) cm-'. Mass (12 eV, g * M23.78%, ~ mle): 334 (M'), 306 (M' - CO),258 (M' PMe3).'H NMR (400.1M H z , benzene-de): 6 -0.04 (ddd, 1 H, H'), 1.02 (d, 3 H,CHJ,1.82 (ddd, 1 H,H2),2.48 (t, 1H,H4),3.86 (td, 1 H,H3), 4.58 (d, C5H5), 4.81 (dd, 1 H,H7),5.48 (dd, 1 H, He),5.83 (dt, 1 H,H5), 5 ~ = 8.5 4 MHz, ~ ~ J P - C ~ H ~= 1.4 Hz, Jp-1 = 12.0 Hz, Jp-2 = 4.6 Hz, 512 = 1.4 Hz, 5 1 3 = 10.2 Hz, 5 2 3 = 6.6 Hz,5 3 4 = 10.2 Hz,545 = 10.2 Hz,5 5 7 = 16.8 Hz,556 = 10.2 Hz, J67= 1.2 Hz. 13C('H)NMR (100.6M H z ,benzene-d,): 6 21.6 (d, PCH,,J p c = 29 Hz),31.1 (d, CH1H2,J p c = 14 Hz),62.8,68.3(CH3 + CH4),108.4 (CH6H7),141.6(CH5),248.0 (d, CO,J p c = 22 Hz).
~ Acknowledgment. We wish to thank Chinese National Science Council for financial support of this work. We also wish t o express gratitude t o Professor R. D. E r n s t for kindly informing us of his results,13bprior t o publication. Registry No. 1, 104293-11-0; 2, 112373-46-3; 3, 112373-48-5; 4,112373-49-6; 5, 112373-50-9; 6,112373-51-0; 7,112373-47-4; 8, 104293-12-1; 9,104293-13-2; 10 (ex0 isomer), 112373-52-1; 10 (endo isomer), 112455-87-5; 11, 112373-53-2; 12,112373-54-3; 13 (exo isomer), 112457-41-7;13 (endo isomer), 112373-58-7;14, 112373-55-4;15, 112373-56-5;16, 112373-57-6; CPMO(CO)~N~, 12107-35-6;PMe2Ph,672-66-2;PMe3,594-09-2;P(CH2CH3)3, 554-70-1; (E,E)-l-chlorohexa-2,4-diene, 17100-75-3; tetracyanomaleicanhydride, 108-31-6. ethylene, 670-54-2;
Synthesis and Asymmetric Reactivity of Enantiomerically Pure Cyclopentadienylmetal Complexes Derived from the Chiral Pool Ronald L. Halterman and K. Peter C. Vollhardt Department of Chemistty, University of California, Berkeley, and the Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94 720 Received July 28, 1987
Starting from pulegone, camphor, and tartrate, three chiral cyclopentadienes were prepared efficiently. ) ~ Tic&resulted in new chiral and enantiomerically pure substituted cycloMetalation with C O ~ ( C Oand pentadienyldicarbonylcobalt and -titanocene complexes. The latter were used in the quantitative catalytic asymmetric hydrogenation of 2-phenyl-1-butene in up to 34% optical yield. The former allowed the first asymmetric [2 2 21 cycloadditions promoted by chiral cyclopentadienylcobaltcomplexes to be observed.
+ +
Introduction Organometallic compounds containing chiral ligands have recently been regarded with intense interest as potential mediators of enantioselective transf0rmations.l Although transition-metal complexes attached to the most common auxiliary, chiral chelating diphosphines,1,2have been used successfully in several c a ~ e s , l -their ~ stereodifferentiating ability can suffer d u e to their lability as complexing agents. In order for efficient transfer of asymmetry to a substrate t o occur, t h e chiral ligand must be bound t o t h e metal during t h e stereodifferentiating step. T h e relatively weak bonding ability of many such ligands is a potential drawback t h a t can limit their applications a n d invites t h e use of a more stable system. We chose as a n +University of California, Berkeley.
example t h e s5-cyclopentadienyl unit because of t h e superior tenacity with which it attaches itself t o transition metals, involving bond strengths as high as 118 kcal m01-l.~ (1)ApSimon, J. W.; Collier, T. L. Tetrahedron 1986, 42, 5157. Paquette, L.A. In Asymmetric Synthesis; Morrison, J. D., Ed.; Academic: New York, 1984;Vol. 3, p 455. Oppolzer, W. Angew. Chem., Znt. Ed. Engl. 1984, 23, 876. ApSimon, J. W.; Seguin, R. P. Tetrahedron 1979, 35, 2797. Valentine, D.,Jr.; Scott, J. W.Synthesis 1978, 329. (2) (a) Kagan, H. B. In Asymmetric Synthesis; Morrison, J. D., Ed.; Academic: New York, 1984;Vol. 5,p 1. (b) Knowles, W. S. Acc. Chem. Res. 1983,16, 106. (c) Kagan, H.B. In Comprehensiue Organometallic Chemistry; Wilkinson, G., Stone, F. G. A., Abel, E. W., Eds.; Pergamon: New York, 1982;Vol. 8,p 463. (3)See also: (a) Koenig, K. E. In Asymmetric Synthesis; Morrison, J. D., Ed.; Academic: New York, 1984;Vol. 5, p 71. (b) For a recent reference, see: Takaya, H.; Ohta, T.; Sayo, N.; Kumobayashi, H.; Akutagawa, S.; Inoue, S.; Kasahara, I.; Noyori, R. J . Am. Chem. SOC.1987, 109, 1596. (4)Jacobson, D.B.;Freiser, B. S. J. Am. Chem. SOC.1985, 107, 7399.
0276-1333188/2307-0883$01.50/0 0 1988 American Chemical Society
884 Organometallics, Vol. 7, No. 4, 1988
Halterman and Vollhardt
At the outset of this work: there were only few examples of chiral and even fewer of optically active cyclopentadiene~,2"~ the most commonly used being the menthol-derived dienes 1 and 2. Although these and related compounds are readily obtained, their metal complexes have effected only modest stereoselectivity in catalytic asymmetric transformation^.^^' Thus, in order to increase the number of potentially stereodifferentiating chiral cyclopentadienyl ligands, it was desirable to develop new expeditions and hopefully general routes to such species starting from inexpensive naturally occurring enantiomerically pure compounds. A more specific goal was to gain access to structures in which the chiral framework either was relatively bulky or was annelated to the fivemembered ring, thus providing a perhaps advantageous more encumbered and/or rigid asymmetric environment to the metal. As a convenient test for their utility, applications in enantioselective titanocene-catalyzed hydrogenations' were envisaged, in addition to the novel exploitation of (~5-cyclopentadienyl)cobalt complexes as mediators of similarly selective carbon-carbon bond formations in [2 + 2 21 cycloaddition reactions of alkynes to other unsaturated moieties.s
+
bQ
H3c*cH3
/
Scheme I"
H3C-fCH3 C6H5
C6H5
8 R=H
7
9 R=4-CH3CgH4502 10 R : CHjSO:!
95-$7%
OH
C6H5
C6H5
11
12 R : 4 - C H 3 C 6 H 4 S O 2 13 R = C H 3 S O z
H3C-fCH3 CgH5
14
,,(a) L-Selectride, T H F , 0 "C, 4 h. (b) CH3SO2C1,pyr, 2 "C, 14 h. (c) NaC5H5, T H F , 12 h, 23 "C, 2 h, A. (d) 4-CH3C6H4S02C1, pyr, 2 "C, 40 h or CH3SOZC1, EtSN, CH2C12,-10 "C, 40 min. Scheme 11"
6..Q
H3 ~ / ' \ ~H
16
17
2
1
Toward these ends, we describe herein the efficient syntheses of 3 (three steps, 36% yield from phenylmenthone), 4 (five steps, 37% yield from camphor), and 5 [one step, 31% yield from threitol bis(4-methylbenzenesulfonate)]. Metalation of these ligands led to chiral titanocene dichloride and (q5-cyclopentadienyl)dicarbonylcobalt complexes whose activity in enantioselective transformations was tested.
18
19
20 C6H5
3
4
5
Results and Discussion Synthesis of 3. On the basis of the report that cyclopentadienes 1 and 2 were accessible by introducing the (5)For a preliminary report, see: Halterman, R. L.; Vollhardt, K. P. C. Tetrahedron Lett. 1986,27, 1461. (6) See, for example: (a) Cesarotti, E.; Chiesa, A.; Ciani, G. F.; Sironi, A.; Vefghi, R.; White, C. J. Chem. SOC.,Dalton Trans. 1984, 653. (b) Dormond, A,; El Bouadili, A,; Moise, C. Tetrahedron Lett. 1983,24,3087. (c) Sato, F.; Iijima, S.; Sato, M. J.Chem. SOC.,Chem. Commun. 1981,180. (d) Cesarotti, E.; Ciani, G.;Sironi, A. J. Organomet. Chem. 1981,216,87. (e) Cesarotti, E.; Ugo, R.; Vitiello, R. J . Mol. Catal. 1981, 12, 63. (0 Couturier, S.; Tainturier, G.; Gautheron, B. J.Organomet. Chem. 1980, 195, 291. (9) Cullen, W.R.; Einstein, F. W. B.; Huang, C.-H.; Willis, A. C.; Yeh, E.-S. J. Am. Chem. SOC. 1980, 102, 988. (h) Fiaud, J. C.; Malleron, J. L. Tetrahedron Lett. 1980,21, 4437. (i) Tamao, K.; Hayashi, T.; Mateumoto, H.; Yamamoto, H.; Kumada, M. Tetrahedron Lett. 1979, 2155. (j)Cesarotti, E.;Ugo, R.; Kagan, H. B. Angew. Chem., I n t . E d . Engl. 1979, 18, 779. (k) Dormond, A.; Kolavudh, T.; Tirouflet, J. J. Organomet. Chem. 1979,164, 317. (1) Cesarotti, E.; Kagan, H. B.; Goddard, R.; Krager, C. J. Organomet. Chem. 1978,162, 297. (m) Leblanc, J. C.; Moise, C. J. Organomet. Chem. 1977, 131, 35; 1976, 120, 65. (n) Marquarding, D.; Burghard, H.; Ugi, I.; Urban, R.; Klusacek, H. J. Chem. Res., Synop. 1977,82. (0)Le Plouzennec, M.; Le Moigne, F.; Dabard, R. J. Organomet. Chem. 1976, 111, C38. (p) See also: Sternbach, D. D.; Hobbs, S. H. S y n t h . Commun.1984,14,1305and the references therein. (7) For other recent work, see: (a) McLaughlin, M. L.; McKinney, J. A.; Paquette, L. A. Tetrahedron Lett. 1986, 27,5595. (b) Paquette, L. A.; McKinney, J. A.; McLaughlin, M. L.; Rheingold, A. L. Tetrahedron Lett. 1986, 27, 5599. (8) Vollhardt, K. P. C. Angew. Chem., Int. E d . Engl. 1984, 23, 539.
a (a) 1, [(CH3)2CH]2NLi,THF; 2, BrCH2CO2CH,, -78 to 23 "C, 1 h. (b) NaOCH,, CH,OH, 23 "C, 16 h. (c) LiCH,P(O)(OCH,),, T H F , -78 "C, 2 h, A, 18 h. (d) NaH, T H F , A, 18 h. (e) LiA1H4, Et20, 23 "C, 30 min. (f) 4-CH,C6H4SO3H, CsH6, 23 "C, 12 h.
future K ligand through alkylation of cyclopentadienyl anion by the 4-methylbenzenesulfonates of neomenthol and menthol,@-JJ respectively, it was anticipated that the more bulky phenylmenthol-derived cyclopentadienes 3 and 6 would also be available by this route. These systems were chosen with the expectation that their complexes would reveal improved stereodifferentiating ability compared to 1 and 2.9 Phenylmenthol(1 l), the projected precursor to 6, was prepared in three steps by literature procedures from pulegone.'O Reduction of phenylmenthone (7) with K-Selectride (Aldrich) gave equivalent amounts of phenylmenthol (11) and neophenylmenthol (S), while L-Selectride (A1drich)l' reduction produced only the desired 8 necessary for the synthesis of 3 (Scheme I). Attempted 4-methylbenzenesulfonation of 8 to give 9 failed, perhaps due to steric congestion, whereas treatment with meth(9) See: Oppolzer, W.; Kurth, M.; Reichlin, D.; Moffatt, F. Tetrahedron Lett. 1981, 22, 2545. (10) Corey, E. J.; Ensley, H. E. J. Am. Chem. SOC. 1975, 97, 6908. (11) The starting phenylmenthone consisted of an 85:15 mixture of diastereomers that could be separated by preparative HPLC. More conveniently, the mixture was reduced and the alcohols were separated by flash chromatography to provide pure 7 in 78% yield: Brown, H. C.; Krishnamurthy, S. J. Am. Chem. SOC. 1972, 94, 7159.
Organometallics, Vol. 7, No. 4, 1988 885
Synthesis of Cyclopentadienylmetal Complexes
anesulfonyl chloride afforded methanesulfonate 10 quantitatively. Gratifyingly, reaction of IO with cyclopentadienylsodium proceeded as planned to furnish the cyclopentadiene 3, in addition to its 2-cyclopentadienyl isomer (ratio 2:l). Unfortunately, attempts to form the (neophenylmenthy1)cyclopentadiene (6) proved to be unsuccessful. Both the 4-methylbenzenesulfonate 12 and the methanesulfonate 13 of phenylmenthol (11) were readily formed, but both failed to alkylate cyclopentadienylsodium under a variety of conditions involving changes in temperature (20 or 66 "C) and solvent (THF or THF/DMPU12). In all cases, only the elimination product 14 was formed. Evidently, the bulky phenyl-substituted group cis to the entering nucleophile creates too much steric hindrance for facile substitution to occur, allowing for competing elimination. Synthesis of 4. Because the structure of the camphor-derived diene 4 incorporates a rigid chiral auxiliary fused to the cyclopentadienyl moiety, it was of particular interest to examine this ligand in potentially enantioselective CpM-mediated transformations. A synthesis of 4 had been reported previ~usly,'~ but attempts to repeat the published preparation on a scale larger than described failed. Hence a new route to this ligand was developed. As a synthetic strategy a cyclopentannulation was chosen, involving the alkylation of camphor by a suitable threecarbon synthon, followed by ring-closure to the corresponding cyclopentenone (Scheme II).I4 Thus, alkylation of (+)-camphor (15) with methyl bromoethanoate (hexane, THF, HMPA) provided keto ester 16.16 This product was of kinetic origin and completely epimerized to 17 in the presence of sodium methoxide. The stereochemistry of these structures was established by using difference nuclear Overhauser effect NMR spectroscopy.l6 Irradiation of one of the geminal dimethyl groups in 16 enhanced the ethanoate methylene signals while the analogous experiment with isomer 17 caused an increase in the magnitude of the tertiary hydrogen resonance. According to a published synthetic pr~cedure,'~ the ketone carbonyl function in 16 (and/or 17) was to be protected as the acetal before addition of the methyl phosphonate unit required for five-membered ring formation, in order to ensure reaction at the normally less reactive ester moiety. However, attempts to form the desired ethylene acetal failed, indicating steric encumbrance at that position. This finding was exploited by reaction of 16 directly with the anion of dimethyl methylphosphonate that led to phosphonate 18 as a single epimer. Deprotonation of this intermediate with sodium or potassium hydride in THF followed by heating to reflux for 18 h effected ring closure to cyclopentenone 19 as a single isomer. In contrast, the lithium salt of 18 failed to cyclize even after several days in boiling THF or THFHMPA. However, addition of dimethyl (lithiomethyl)phosphonate to 16 in diglyme at -78 OC followed by heating to reflux for 18 h gave 19 directly (51% mixture
Scheme 111"
A a
22
(a) NaC5H5,NaH, 23 OC, 8 h, A, 2 h.
of epimers). Reduction of 19 with lithium aluminum hydride in ether" resulted in the acid-sensitive alcohol 20 in nearly quantitative yield. When this reduction was carried out in THF, a mixture of products ensued. Dehydration of 20 in benzene was accomplished overnight in the presence of 4-methylbenzenesulfonic acid to form the apparently thermodynamically favored diene 41331s as a clear oil. Synthesis of 5. The tartrate-derived 21 could, in principle, be convertible to the chiral cyclopentadiene 5 via double displacement of both leaving groups by the cyclopentadienyl moiety (Scheme 111). However, similar transformations in the literaturelg had led to the spiro compounds related to the potential product 22 of our scheme. Fortunately, treatment of commercial 2120 with cyclopentadienylsodium and sodium hydride provided crystalline 5 as the only isolable product. Evidently, deprotonation of the initially formed intermediate diene A induced displacement of the second leaving group to give the annulated product 5 of a subsequent facile hydrogen migration.21 Spiroannulation seems to be unfavorable here, perhaps because of the presence of the trans-fused bicyclo[3.3.0]octane framework in 22. Metalation of 3. Diene 3 was readily converted (65%) into complex 23 by treatment with octacarbonyldicobalt. The structure of this compound was evident from its spectral characteristics. The stereochemistry shown was strongly suggested by examination of the 'H NMR spectrum. The tertiary hydrogen at the carbon bearing the cyclopentadienyl ring appears as a slightly broadened doublet of doublets ( J = 11, 10.5 Hz). This finding is in agreement with the presence of two large axid-axid 3&-H and a small axial-equatorial 3JH-H coupling, as expected for 23. Metalation of the anion of diene 3 with titanium trichloride (0.5 equiv) followed by addition of hydrochloric acid22furnished titano'cene dichloride 24 (45%). Its C2 symmetry was reflected by the observation of only 19 I3C NMR signals. The stereochemistry was again indicated by 'H NMR specroscopy; the tertiary hydrogen at C-2 bearing the cyclopentadienylring gave rise to the expected broad doublet of doublets (J = 10, 10 Hz). Metalation of 4. Exposure of 4 to octacarbonyldicobalt resulted in a 3:l mixture of the inseparable isomeric complexes 25a and 25b. A definitive stereochemical assign~~
~~
(17)Brown, H.C.;Hess, H. M. J. Org. Chem. 1969,34, 2206. (12)DMPU = 1,3-dimethyl-3,4,5,6-tetrahydro-2(lH)-pyimidinone: (18)Bohm, M.C.; Carr, R. V. C.; Gleiter, R.; Paquette, L. A. J. A m . 1980,102,7218. Bartlett, P. D.;Wu, C. J. Am. Chem. SOC. Chem. SOC. Mukhopadhyay, T.; Seebach, D. Helu. Chim. Acta 1982,65,385. (13)Compound 4 has been prepared by a bis Wittig reaction on cam1983,105, 100. phor quinone in low yield and with an optical rotation at odds with our (19)Hallam, B. F.;Pauson, P. L. J. Chem. SOC. 1958,646. Antczak, K.; Kingston, J. F.; Fallis, A. G. Can. J. Chem. 1984,62,2451. results: Burgstahler, A. W.; Boger, D. L.; Naik, N. C. Tetrahedron 1976, 32, 309. (20)Compound 21 is available from Aldrich Chemical Co. or it can be (14)Clark, R. D.;Kozar, L. G.; Heathcock, C. H. Synth. Commun. readily synthesized in three steps from diethyl tartrate: Townsend, J. 1975,5 , 1. M.; Blount, J. F.; Sun,R. C.; Zawoiski, S.;Valentine, D., Jr. J.Org. Chem. (15)House, H. 0.; Gall, M.; Olmstead, H. D. J. Org. Chem. 1971,36, 1980,45, 2995. 2361. (21)Mironov, V. A.; Ivanov, A. P.; Kimelfeld, Ya. M.; Petrovskaya, L. (16)Becker, E.D.High Resolution NMR, Theory and Chemical ApI.; Akhrem, A. A. Tetrahedron Lett. 1969,3347. (22)Smith, J. A.; Brintzinger, H. H. J. Organomet. Chem. 1981,218, plications; Academic: New York, 1980. Noggle, J. H.; Schirmer, R. E. 159. The Nuclear Overhauser Effect;Academic: New York, 1971.
886 Organometallics, Vol. 7, No. 4, 1988 /
Halterman and Vollhardt Table I. Catalytic Hydrogenation of 30"
\
K/
H2,Calalysl. toluene
'
HSC6
h/
HSC6
30
24
23
ment of these isomers could not be made. Since both isomers are obtained in comparable amounts, it appears that metalation of the seemingly more sterically hindered exo face may be favored electronically.23
&
H3C
CH3
H3C
/
H3C
H3C
COICO)2
25b
The. camphor-derived titanocene dichloride 26 was synthesized in a manner analogous to that of the preparation of the phenylmethyl-derived complex 24. The crude product was analyzed to consist of a 9 5 5 mixture of isomers by 'H NMR spectroscopy. Recrystallization by slow evaporation of a dichloromethane-isooctane solution gave deep red crystals of the major component (11%).The minor isomer in the crude product mixture was assigned the structure 27 based on the observation of six singlets in the methyl region of its 'H NMR spectrum, revealing lack of Czsymmetry. The major isomer that exhibited such symmetry by NMR could, in principle, have the structures of either 26a or 26b. The arrangement depicted by 26a is to be favored on the basis of the X-ray structural confirmation of a related and the changes in chemical shifts in the 'H NMR spectra when going from 4 to 26a.23 H3CVCH3
j
&
p
3
H3C
\
H3C H
H3C'
'CH3
260
26 b
27
Metalation of 5. The problem of stereofacial differentiation encountered in the metalation of the fused camphor-derived diene 4 is avoided in the complexation of the C2-sy"etrical tartrate-derived diene 5. Thus, treatment of 5 with dicobalt octacarbonyl produced the only possible stereoisomer of the dicarbonylcobalt complex 28 as a crystalline red solid (43%1. Unfortunately, all attempts to form the corresponding titanocene dichloride 29 were unsuccessful. This failure could be due to reactivity of the acid-sensitive acetal moiety present in 5.
28
3 4
cat. precursor
24 26a 26a 26a
inductn timeb l h 2 min 2 min 2 min
"C
temp,
20 20 0
-20
time'
optical yield, %
40 h 20 min 40min 5h
33
22 25 34
"Reactions were performed according to the literature with a substrate to catalyst ratio of 1OO:l; see ref 22. *Time required for the uptake of hydrogen t o begin a t 20 "C after addition of 4 equiv of butyllithium. The solutions were then rapidly cooled (when necessary) to the reaction temperatures shown in column 4. The time required for quantitative reaction to reach completion as determined by gas chromatography.
CHI
&'co""
250
entry 1 2
31
29
Asymmetric Hydrogenations. In order to establish whether the ligands 3-5 were able to transmit their asymmetry while complexed to transition metals engaged in (23) Gallucci, J. C.; Gautheron, B.; Gugelchuk, M.; Meunier, P.; Paquette, L. A. Organometallics 1987, 6, 15. Hsu, L.-y.; Hathaway, S. J.; Paquette, L. A. Tetrahedron Lett. 1984, 25, 259.
organic reactions, hydrogenation of 2-phenyl-1-butene(30) was subjected to scrutiny using as catalyst precursors the titanocene dichlorides 24 and 26a. Reduction of either 24 or 26a by butyllithium in the presence of alkene 30 under hydrogen produced a catalytically active, gray-green solution.22As summarized in Table I, both species catalyzed the uptake of hydrogen after an initial induction period, producing 2-phenylbutane (31) quantitatively in modest optical yields. In the reduction facilitated by 24, hydrogen uptake began 1 h after the addition of butyllithium and the reaction reached completion after 40 h. The 2-phenylbutane so produced was purified by preparative gas chromatography and its optical rotation compared with the maximum reported value,u indicating the achievement of 33% optical yield in this enantioselective hydrogenation. In contrast, hydrogen uptake after reducing 26a occurred within 2 min and alkene 30 was completely reduced within 20 min at 20 "C. The optical yield in this case was 22%. The activation of 26a by butyllithium at 0 "C failed, necessitating 20 "C, followed by cooling of the reaction mixture to the temperature indicated in Table I for the duration of the hydrogenation. In this way, optical yields of product up to 25% and 34% were obtained after 40 min at 0 "C and 5 h at -20 "C, respectively. The results achieved here are the best yet reported and bode well for other synthetic applications of these two ligands. The lesser reactivity of the phenylmenthol-derived24, relative to camphor-derived 26a and the other reported menthol-derived catalysts, may be due to increased steric hindrance encumbering both reduction of the metal and access of the substrate to the active site. Diastereoselective Cobalt-Mediated Photolytic Alkyne Cyclizations to Complexed Cyclopentadienones. The availability of the new chiral cyclopentadienylcobalt complexes 23, 25, and 28 suggested an investigation of their potential in cobalt-mediated asymmetric C-C bond formations.* An initial exploration of this potential focused on the photolytical cyclization of unsymmetrical a,@-diynes32 to metal-complexed cyclopentadienones 33.25
CR'
CpCo(COI2.hv
=-R2
32
'
(+ cpco
RZ
33
(24) Lardicci, L.; Menicagli, R.; Salvadori, P. Gazr. Chim. Ital. 1968, 98,138. (25) Gesing, E. R. F.; Tane, J. P.; Vollhardt. K. P. C. Angew. Chem., Int. E d . Engl. 1980, 19, 1023.
Organometallics, Vol. 7, No. 4, 1988 887
Synthesis of Cyclopentadienylmetal Complexes Table 11. Stereoselectivity in the Formation of Cyclopentadienone Complexes 33 in the Cyclization of 32 Mediated by Cobalt Complexes 23 and 28 R'
32
entry 1 2
3 4 5 6
23 or 2 8
diyne 32 R' R2 Si(CH& H Si(CH3)3 CH3 Si(CH3)3 CH3CH2 CH3 H CHSCH2 H Si(CH3I3 CH3CH2
33
Cp*Co(CO), 23 23 23 23
23 28
yield of 33, %
54 64 74 53 54 64
diastereomeric ratio of 33" 52:48 67:33 6040 61:39 56:44 50:50
Ratio determined by lH NMR integration of several characteristic signals.
The required diynes 32 were synthesized by standard methods.26 A degassed T H F solution of 32 and the respective cobalt complex was irradiated at -20 "C with a 450-W Hanovia mercury vapor lamp for 6 hZ5to result in the data presented in Table 11. While the complex 28 gave modest diastereoselectivity in these reactions, 23 exhibited no such effect. The diastereomers of 33, entries 1-3 and 6, could be separated by silica gel chromatography, the minor isomer eluting first. The moderate yields of 33 are due to the formation of the usual side products in these transformations, alkyne trimers and cyclobutadiene complexes2' (not isolated in the present cases). Because of relatively low yields and modest stereoselectivities, it is hard to reach any conclusion regarding the mechanistic origin of the asymmetric induction in these transformations. Nevertheless, the results demonstrate for the first time the feasibility of achieving such selectivity. Diastereoselective Enediyne Cyclizations to Complexed Cyclohexadienes. Prochiral a,?j,w-enediynescyclize to chiral tricyclic diene complexes in the presence of C ~ C O ( C O ~When ) . ~ enediyne 3428 was subjected to 23 under the usual cyclization conditions, a 58:42 mixture of the diastereomeric complexes 35 ensued, the position of the metal relative to the tertiary hydrogen tentatively assigned to be exo, based on the relatively high-field position of the 'H NMR signals of the latter (6 -0.45). While again the diastereomeric excess (16%; additional stereochemistry unassigned) was only moderate (although nevertheless remarkable considering that four diastereomers could have been formed), it indicates that perhaps by appropriate fine-tuning of ligands and substrate, useful selectivities may be attained, a subject worthy of continuing i n v e s t i g a t i ~ n . ~ ~
34
35
(26) (a) Birkofer,L.; Hiinsel, E.; Steigel,A. Chem. Ber. 1982,115, 2574. (b) Emptoz, G.; Vo-Quang, L.; Vo-Quang, Y . Bull. SOC.Chim. Fr. 1965, 2653. (c) Naiman, A.; Vollhardt, K. P. C. Angew. Chem.,Znt. Ed. Engl. 1977, 16, 708. (27) Gesing, E. R. F.; Vollhardt, K. P. C. J. Organomet. Chem. 1981, 217, 105. (28) Stemberg, E. D.; Vollhardt, K. P. C. J.Am. Chem. SOC.1980,102, 4839. Sternberg, E. D.; Vollhardt, K. P.C. J. Org. Chem. 1984,49,1564. (29) Halterman, R. L.; Vollhardt, K. P. C.; Welker, M. E.; Blaser, D.; Boese, R. J. Am. Chem. SOC.1987,109, 8105-8107.
Experimental Section General Data. Unless otherwise noted, all starting materials were obtained from commercial suppliers and used without further purification. THF and ether were distilled from sodium benzophenone ketyl. All reactions involving air- or moisture-sensitive organometallic reagents were carried out under dry nitrogen in flame-dried glassware. Solvents for such reactions were dried by standard methods. Vacuum line operations utilized a multiple-line apparatus. 'H and 13C NMR spectra were recorded on UCB-200 MHz, UCB-250 MHz, and UCB-300 MHz instruments consisting of Cryomagnet System magnets, Nicolet 293A or 293A' pulse programmers, and Nicolet Model 1180 or 1180E data collection systems or on a Bruker AM-500 MHz model. Data are reported as follows: chemical shifts in parts per million (ppm) relative to internal tetramethylsilane or residual solvent peaks (multiplicity, coupling constants in hertz, number of hydrogens). For 'H NMR spectra, the peak due to residual CHC13is listed at 7.24 ppm, and for 13C NMR spectra, the central peak of the CDCl, triplet is assigned a chemical shift of 77.0 ppm. Off-resonance decoupled (off-reson decoup) 13C NMR spectra were obtained for some compounds as indicated. The multiplicities observed are indicated as s (singlet), d (doublet), t (triplet), and q (quartet). DEPT 13C NMR spectra30 are also indicated for some compounds. The nature of the carbon is indicated as quat (quaternary), CH (methine), CH2 (methylene), and CH3 (methyl). Infrared spectra were obtained on one of the Perkin-Elmer Models 681 or 1420 and were referenced to polystyrene (1601 cm-'). Only characteristic and/or strong signals are reported. Low-resolution mass spectra [reported as m/z (relative intensity) a t 70 eV], high resolution mass spectra (HRMS), and elemental analyses were provided by the Mass Spectral Service and Microanalytical Laboratory, respectively, a t the University of California, Berkeley. Melting points were determined in open Pyrex capillary tubes with a Thomas-Hoover Unimelt apparatus and are uncorrected. Column chromatography was performed on activity 3 alumina 60 mesh, deactivated with (Alfa products, activated neutral A1203, 6% w/w (water) or flash silica (E. Merck Reagents silica gel 60, 230-400 mesh ASTM). High performance liquid chromatography (HPLC) was performed on an Altex Model 330 isocratic liquid chromatographic system with a Hitachi 100-10W-visible detector or an Altex 153 UV detector. Two Altex 5-wm-Ultrasphere-ODS reverse phase columns were utilized in sequence. All HPLC solvents were millipore-filtered and saturated with argon prior to use. Analytical gas chromatography was carried out on a Hewlett-Packard Model 5880 gas chromatograph equipped with a 12 m X 0.25 mm OV-101 glass capillary column or a 3 m X 2 mm 3% OV-101 on WHF 80/100 glass column. Preparative gas chromatography was executed on a Varian Model 920 instrument equipped with a stainless-stell 2 m X 7 mm 10% SE-30 on 60-80 mesh Chromosorb AW column. Optical rotations were measured on a Perkin-Elmer Model 241 polarimeter a t 26 "C using a 1-dm quartz cell holding 1 mL. (1S,2S,5R )-5-Methyl-2-(2-phenyl-2-propyl)c yclohexanol (8) and (1R,2R,5R)-5-Methyl-2-(2-phenyl-2-propyl)cyclohexanol. To an L-Selectride solution (75.0 mL, 1.0 M in THF, 75.0 mmol) at 0 OC was added dropwise via syringe a solution of 7 (11.52 g, 50.00 mmol, 8515 mixture of diastereomers) in T H F (50 mL). The reaction mixture was stirred for 4 h at 0 OC at which point aqueous NaOH (26.0 mL, 3.0 M, 48.0 mmol) was added dropwise followed by slow addition of 30% H202(26.0 mL, 10 M, 260 mmol) resulting in an exothermic reaction. The solution was allowed to warm to room temperature, stirred for 30 min, and extracted with ether (5 X 20 mL). The combined organic portions were washed with water (10 mL) and dried over MgS04. The solvent was removed to give a mixture of 8 and its isomer as an oil (11.23 g, 96.7%) separated by flash chromatography (4% ether in hexanes) to yield f i s t the minor (lR,2R,5R)-isomer (1.32 g, 76% based on the starting composition of 7): IR (thin film)3410,2974, 2941, 1460, 1381,1335,1042, 707 cm-'; MS, m/z (relative intensity) (30) Doddrell, D. M.; Pegg, D. T.; Bendall, M. R. J. Magn. Reson. 1982,48,323. Pegg, D. T.; Doddrell, D. M.; Bendall, M. R. J. Chem. Phys. 1982, 77, 2145.
888 Organometallics, Vol. 7, No. 4, 1988
Halterman and Vollhardt
215 (3), 119 (loo), 105 (20), 91 (22), 59 (17), 57 (38); 'H NMR (300 = 8.3 Hz, 2 HI, 7.08-7.22 (m, 5 H), 4.77 (ddd, J = 10.6, 10.6, 4.3 MHz, CDC13) 6 7.42 (dd, J = 7.4, 1.0 Hz, 2 H), 7.33 (dd, J = 7.7, Hz, 1 H), 2.42 (s, 3 H), 2.18 (br d, J = 10.6 Hz, 1 H),1.94 (ddd, 7.4 Hz, 2 H), 7.21 (td, J = 7.7, 1.0 Hz, 1 H), 3.87 (br s, 1 H), J = 10.6,10.2, 3.4 Hz, 1H), 1.30-1.50 (m, 3 H), 1.35 (s, 3 H), 1.28 1.76-1.94 (m, 2 H), 1.46-1.66 (m, 3 H), 1.45 (s,3 H), 1.43 (8, 3 H), (s, 3 H), 1.16 (m, 1 H), 0.92 (dddd, J = 13.3, 13.0, 13.0, 3.1 Hz, 1.21 (m, 1H), 1.16 (d, J = 7.4 Hz, 3 H), 0.92 (m, 2 H); 13CNMR 1H), 0.81 (d, J = 6.3 Hz, 3 H), 0.70 (m, 1H); 13CNMR (75.5 MHz, (75.5 MHz, CDCl,, DEPT) 6 149.8 (quat), 127.9 (CH), 126.1 (CH), CDC13) 6 150.6, 144.1, 135.6, 129.5, 127.9, 127.4, 125.4, 125.1, 84.3, 51.3, 42.8, 40.1, 34.1, 31.6, 28.9, 27.3, 23.6, 21.6; [(u]'*D 5.48' (C 125.4 (CH), 69.0 (CH), 52.6 (CH), 40.4 (CH,), 40.3 (quat), 32.8 0.1465, ethanol). Anal. Calcd for C23H3003S:C, 71.48; H, 7.82. (CH,),27.6 (CH,), 26.4 (CH), 25.5 (CH,), 21.2 (CH,), 16.4 (CHZ). Anal. Calcd for C16H240: C, 82.70; H, 10.41. Found: c, 82.81; Found: C, 71.06; H, 7.90. H, 10.55. Attempted Synthesis of 6 from 12. Formation of A second fraction was identified as pure 8 (9.07 g, 92% based (3R,6R)-6-Methyl-3-(2-phenyl-2-propyl)cyclohexene (14). A solution of cyclopentadienylsodium-dimethoxyethane(0,991 g, on the starting composition of 7): IR (thin film) 3399,2975,2884, 3.00 mmol) in T H F (5 mL) was added at 0 "C to a solution of 1466,1403,1335,1265,1124,1039,973,708cm-'; MS, m/z (relative intensity) 232 (M', O.l), 214 (2), 119 (loo), 105 (20), 91 (25), 77 12 (0.865 g, 4.5 mmol) in THF (25 mL). The reaction mixture (4); 'H NMR (500 MHz, CDC1,) 6 7.38 (dd, J = 7.7, 1.0 Hz, 2 H), was heated at reflux for 6 h, cooled to room temperature, and 7.31 (dd, J = 7.7, 7.3 Hz, 2 H), 7.18 (td, J = 7.3, 1.0 Hz, 1H), 3.86 worked up with acidic (NH4C1)water and the residue filtered (br s, 1H), 1.68-1.76 (m, 2 H), 1.64 (dddd, J = 13.5,3.5, 3.0,2.5 through a flash silica column (hexanes) to afford a colorless liquid Hz, 1 H), 1.48-1.57 (m, 2 H), 1.45 (ddd, J = 13.5, 3.0, 1.7 Hz, 1 (0.537 g, 56%). 'H NMR analysis showed this product to be H), 1.40 (s, 3 H), 1.38 (s, 3 H), 1.11(m, 1H), 1.02 (ddd, J = 13.5, approximately 90% pure 14: IR (thin film) 2957,1603,1497,1446, 11.5, 2.2 Hz, 1 H), 0.87 (m, 1 H), 0.83 (d, J = 6.3 Hz, 3 H); 13C 1369, 1115,1034,766,702 cm-'; MS, m / z (relative intensity) 214 (M', l), 199 (l),119 (loo), 105 (4), 95 ( 5 ) ,91 (26),79 (7); 'H NMR NMR (75.5 MHz, CDCl,, DEPT) 6 149.8 (quat), 128.0 (CH), 126.2 (300 MHz, CDCI,) 6 7.10-7.40 (m, 5 H), 5.57 (m, 2 H), 2.49 (m, (CH), 125.5 (CH), 68.2 (CH), 52.2 (CH), 43.8 (CH,), 40.2 (quat), 1 H), 2.08 (m, 1 H), 1.85 (m, 1 H), 1.61 (m, 1 H), 1.44 (m, 1 H), 35.6 (CH,), 27.6 (CH,), 26.1 (CH), 25.8 (CH,), 22.2 (CH,), 21.3 1.38 (s, 3 H), 1.35 (s, 3 H), 1.17 (m, 1 H), 0.99 (d, J = 6.4 Hz, 3 (CH,). Anal. Calcd for Cl6HZ4O:C, 82.70; H, 10.41. Found C, H); 13CNMR (75.5 MHz, CDC1,) 6 149.7, 134.9, 128.1, 127.9 (2 82.76; H, 10.51. C), 126.1 (2 C), 125.4, 46.7, 40.2, 32.4, 30.9, 25.2, 24.9, 24.8, 22.0. ( 1 s ,2S ,5R )-5-Methyl-2-(2-phenyl-2-propyl)cyclohexyl Anal. Calcd for C16H22: C, 89.65; H, 10.34. Found: C, 89.68; H, Methanesulfonate (10). To pyridine (4 mL) at -10 "C under 9.99. nitrogen was added via syringe freshly distilled methanesulfonyl (1R ,2S,5R)-5-Methy1-2-(2-phenyl-2-propyl)cyclohexyl chloride (0.802 g, 7.00 "01). A solution of 8 (1.162 g, 5.00 "01) Methanesulfonate (13). To a solution of 11'O (4.64 g, 20.0 mmol) in pyridine (1mL) was added dropwise. The mixture was stirred and triethylamine (3.03 g, 30.0 mmol) in dichloromethane (100 at this temperature for 30 min and then for 14 h at 2 OC. Aqueous mL) at -10 "C was slowly addded methanesulfonyl chloride (3.44 workup provided 10 as a thick, thermally sensitive yellow oil (1.536 g, 30.0 mmol) over 10 min. Aqueous workup gave crude 13 as g, 99.0%): IR (thin film) 2954, 1498, 1457, 1346, 1176, 899, 704 a pale yellow oil (6.61 g, 96.7%): IR (thin film) 2956, 1603,1499, cm-'; 'H NMR (300 MHz, CDC1,) 6 7.32 (m, 4 H), 7.18 (m, 1 H), 1447,1338, 1178,918, 707 cm-'; 'H NMR (300 MHz, CDC1,) 6 4.90 (br s, 1 H), 2.90 ( 8 , 3 H), 2.18 (dddd, J = 14.5, 3.5, 3.0, 2.5 7.05-7.30 (m, 5 H), 4.65 (ddd, J = 10.5, 10.5, 3.5 Hz, 1 H), 2.43 Hz, 1H), 1.79 (m, 1 H), 1.77 (br d, J = 13.0 Hz, 1 H), 1.48-1.67 (s, 3 H), 2.28 (m, 1 H), 2.04 (ddd, J = 10.5, 10.2, 3.4 Hz, 1 H), (m, 3 H), 1.39 (s, 3 H), 1.35 (s, 3 H), 1.08 (ddd, J = 13.0, 13.0, 1.60 (m, 3 H), 1.40 (m, 1 H), 1.37 (s, 3 H), 1.19 (8, 3 H), 1.10 (m, 1.5 Hz, 1 H), 0.91 (m, 1H), 0.86 (d, J = 6.4 Hz, 3 H); 13CNMR (75.5 MHz, CDCl3, DEPT) 6 148.9 (quat), 128.0 (CH), 126.0 (CH), 1 H), 0.81 (d, J = 6.4 Hz, 3 H), 0.79 (m, 1 H). This thermally sensitive product was used without further purification in the next 125.7 (CH), 80.7 (CH), 51.7 (CH), 40.6 (CH,), 39.8 (quat), 39.4 step. (CH,), 34.9 (CHZ), 26.6 (CH,), 26.2 (CH), 25.1 (CH,), 21.8 (CH,), Attempted Synthesis of 6 from 13. A solution of cyclo21.7 (CH& "his product was used in the next step without further pentadienylsodium-dimethoxyethane (1.40g, 3.62 mmol) in THF purification. (1R ,2R ,5R)-l-Cyclopentadienyl-5-methyl-2-(2-pheny1-2- (5 mL) was added at 0 'C to a solution of 13 (1.00 g, 5.20 mmol) in THF (15 mL). The reaction mixture was heated at reflux for propy1)cyclohexane (3). To NaH (0.160 g, 60%, 4.00 mmol), 6 h. Aqueous workup yielded 14 (0.492 g, 63.4%) as a colorless washed with pentane (3 X 10 mL) in T H F (15 mL) was added liquid. freshly distilled cyclopentadiene (0.320 g, 4.00 mmol) in THF ( 5 (1R ,3R ,4R )-3-[ (Methoxycarbonyl)methyl]-1,7,7-trimL) under nitrogen at room temperature. The solution evolved methylbicyclo[2.2.1]heptan-2-one (16). To butyllithium (284 gas and was stirred for 20 min. At 0 "C 10 (0.990 g, 3.00 mmol) mL, 1.55 M in hexane, 440 mmol) in dry THF (500 mL) at -78 in T H F (10 mL) was introduced dropwise into the reaction soOC was added dropwise over 10 min distilled diisopropylamine lution. This mixture was stirred at this temperature for 30 min (44.5 g, 440 mmol). After having been stirred for 15 min while and for 12 h at room temperature and then heated at reflux for the temperature was allowed to rise slightly, the solution was 2 h. Acidic (HCl) aqueous workup yielded a yellow oil (0.947 g) cooled to -78 OC and (+)-camphor (15) (60.88 g, 400 mmol) in that was purified by flash chromatography (hexanes) to provide THF (80 mL) was added via cannula over 30 min. After 15 min, 3 as a colorless oil (0.386 g, 45.9%) as a mixture of cyclopentadiene and, after an additional 30 min, methyl HMPA (78.8 g, 440 "01) double-bond isomers: IR (thin film) 3060,2952,2915,1603,1497, bromoacetate (122.3 g, 800 mmol) were added via cannula as 1456,1370,1034,900, 765,702 cm-'; MS, m / z (relative intensity) rapidly as possible (about 30 s). The solution turned yellow while 280 (M', 7), 154 (8), 119 (loo), 105 (14), 91 (59), 79 (25), 67 (14); it was stirred for 30 min at -78 'C. After having been warmed lH NMR (250 MHz, CDC1,) 6 7.05-7.40 (m, 5 H), 6.38 (br s, 0.3 to room temperature over 1 h, the mixture was subjected to basic H), 6.34 (br s, 0.6 H), 6.19 (br s, 1.4 H), 5.91 (br s, 0.7 H), 2.79 (NaHCOJ aqueous workup and the resulting liquid fractionally (br s, 1.4 H), 2.35-2.75 (m, 1.6 H), 1.86 (m, 1 H), 1.35-1.75 (m, distilled under vacuum to yield first recovered camphor (15) (12.3 4 H), 1.30 (m, 1 H), 1.27 (s, 3 H), 1.16 (s, 3 H), 0.90-1.15 (m, 2 H), 0.86 (d, J = 6.4 Hz, 3 H). Anal. Calcd for C2,Hzs: C, 89.94; g) and then 16 as a colorless liquid (54.74 g, 61.0%, 71.6% based H, 10.06. Found: C, 89.71; H, 10.02. on recovered camphor): bp 108-112 OC (0.05 mm): IR (thin film) (lR,2S,5R )-5-Methyl-2-(2-phenyl-2-propyl)cyclohexyl 2962,1740,1439,1394, 1317, 1284,1273,1235, 1198, 1173, 1117, 1087, 1021, 1006 cm-'; MS, m / z (relative intensity) 224 (M', 25), 4-Methylbenzenesulfonate(12). To 4-methylbenzenesulfonyl 192 (47), 157 (20), 150 (26), 121 (30), 108 (52), 95 (95), 83 (loo), chloride (13.35 g, 70.0 mmol) in pyridine (40 mL) at -10 "C was 69 (57), 55 (50);'H NMR (200 MHz, CDCl,) 6 3.70 (s, 3 H), 2.83 slowly added phenylmenthol(ll)lo(11.62 g, 50.0 mmol) in pyridine (dd, J = 16.0, 3.3 Hz, 1 H), 2.45 (dd, J = 9.9, 3.3 Hz, 1 H), 2.32 (10 mL). The mixture was stirred at -10 OC for 30 min and then (dd, J = 16.0,g.g Hz, 1 H), 2.04 (m, 1 H), 1.97 (br d, J = 3.1 Hz, for 40 h at 2 "C. Acidic (H,SO,) aqueous workup gave a thick 1H), 1.65 (m, 1 H), 1.52 (m, 2 H), 0.94 (s, 3 H), 0.91 (s, 3 H), 0.82 yellow oil that was purified by flash chromatography (10% ether (3 H); 13CNMR (50.8 MHz, CDC1,) 6 219.3, 172.8, 57.0,51.6,49.9, in hexanes) to provide colorless crystalline 12 (18.36 g, 95.4%): 47.5, 46.5, 35.5, 28.8 (2 C), 21.2, 20.1, 9.2; [.Iz6~ 33.3' (C 0.261, mp 76.5-77.5 "C; IR (neat) 2958, 1602, 1497, 1457, 1362, 1178, hexane). Anal. Calcd for Cl3HZ0O3:C, 69.61; H, 8.99. Found: 918,870, 704,669 cm-I; MS, m / z (relative intensity) 385 (4), 214 C, 69.36; H, 8.78. (71), 199 (65), 172 (82), 157 (38), 143 (81), 119 (89),91 (100); 'H (1 R ,3S ,4R)-3-[(Methoxycarbonyl)methyl]- 1,7,7-triNMR (300 MHz, CDCI3)6 7.71 (d, J = 8.3 Hz, 2 H), 7.28 (d, J
Synthesis of Cyclopentadienylmetal Complexes
Organometallics, Vol. 7, No. 4, 1988 889
that were then stirred overnight a t room temperature. The acid methylbicyclo[2.2.1]heptan-2-one (17). To sodium (0.092 g, was neutralized with K2C03and the solution dried with MgS04. 4.00 mmol) dissolved in methanol (5 mL) under nitrogen was The solvent was removed by rotary evaporation and the resulting added 16 (0.224 g, 1.00 mmol) in methanol (1mL) via syringe. oil (0.870 g) passed through a short activity 3 alumina column "his mixture was stirred overnight at room temperature. Aqueous with pentane to yield 4 as a colorless oil (0.714 g, 81.9%): IR (thin acidic (HCl) workup resulted in 17 as a colorless oil (0.192 g, 86%): film) 2957,1442,1383,1156,893,759 cm-'; 'H NMR (250 MHz, IR (thin film) 2962,1741,1439,1312,1275,1234,1170,1047 cm-'; CDC13) 6 5.66 (br s, 1 H), 5.60 (9, 1 H), 3.14 (d, J = 23.0 Hz, 1 MS, m / z (relative intensity) 224 (M', 26), 192 (43), 181 (13), 150 H), 3.02 (d, J = 23.0 Hz, 1H), 2.47 (d, J = 3.5 Hz, 1H), 1.99 (dddd, (25), 108 (56), 95 (loo), 83 (76), 55 (69); 'H NMR (300 MHz, J = 11.2,11.0, 3.8,3.5 Hz, 1H), 1.77 (ddd, J = 11.0, 10.5, 2.6 Hz, 2DC1,) 6 3.62 ( 8 , 3 H), 2.83 (ddd, J = 10.2, 5.0, 4.4 Hz, 1H), 2.68 1 H), 1.36 (ddd, J = 11.2, 9.6, 2.6 Hz, 1 HI, 1.27 (ddd, J = 10.5, (dd, J = 16.3, 5.0 Hz, 1 H), 2.18 (dd, J = 16.3,10.2 Hz, 1H), 2.10 9.6,3.8 Hz, 1H), 1.11(s,3 H), 0.94 (s, 3 H), 0.67 (s,3 H); 13CNMR (dd, J = 4.4,4.4 Hz, 1 H), 1.70 (m, 1H), 1.65 (m, 1 H), 1.42 (ddd, (63.1 MHz, CDC1,) 6 159.4, 154.5, 114.9, 113.5, 54.3, 49.1, 48.3, J = 11, 11, 3.4 Hz, 1 H), 1.17 (m, 1 H), 0.94 (s, 3 H), 0.87 ( 8 , 3 44.25,34.6,26.9,20.6,18.2,11.9; [cxIae~5.8' (c 0.376, hexane). The H), 0.85 (s,3 H); 13CNMR (75.5 MHz, CDCl,) 6 218.5,172.1, 57.9, 51.2, 46.1, 46.0,45.4, 31.2, 30.6, 19.8, 19.1, 18.8, 9.0. Anal. Calcd 'H NMR spectrum of this product matched that reported13 at lower field (60 MHz). for C13H&3: C, 69.61; H, 8.99. Found C, 69.34; H, 8.99. The intermediate allylic alcohol 20 could be obtained as a clear (1R,3S ,4R )-3-[3 4Dimethylphosphono)-2-oxoprop-l-yl]oil by drying and removing the solvent after the reduction. It 1,7,7-trimethylbicyclo[2.2.l]heptan-2-one(18). To dimethyl was noted that it was unstable and a higher yield of 4 could be methylphosphonate (0.992 g, 8.00 mmol) in THF (20 mL) at -78 obtained without isolation of 20: 'H NMR (250 MHz, CDC13) 'C was slowly added butyllithium (5.59 mL, 1.43 M in hexane, 6 5.27 (d, J'= 3.0 Hz, 1 H), 5.08 (m, 1H), 2.95 (m, 1 H), 2.86 (br 8.00 mmol) via syringe. After the solution had been stirred for s, 1 H), 2.27 (ddd, J = 11.0, 6.1, 6.1 Hz, 1H), 1.70 (m, 2 H), 1.50 30 min, 16 (0.90 g, 4.01 mmol) in THF (5 I&) was added dropwise. (m, 1 H), 1.20-1.40 (m, 3 H), 1.01 (s, 3 H), 0.97 (s, 3 H), 0.95 ( 8 , The reaction mixture was allowed to warm to room temperature, 3 H); 13CNMR (63.1 MHz, CDC13) 6 165.9, 119.8, 81.7,52.6,50.4, stirred for 1 h, and worked up with water and the resulting oil 50.2, 47.7, 40.7, 40.4, 20.6, 19.8, 19.5, 11.8. (1.05 g, 83.0%) purified by flash chromatography (20% methanol (3S,4S )-3,4-(Dimethylmethylenedioxy)bicyclo[4.3.0]in ethyl acetate) to yield 18 as a colorless oil (0.78 g, 61.3%): IR nona-6,g-diene (5). To sodium hydride (1.76 g, 60%, 44.0 mmol) (thin film) 2961,1740,1723,1261,1189,1035,817 cm-'; MS, m/z (relative intensity) 316 (M', lo), 288 (31), 255 (lo), 205 (28), 151 washed with pentane (3 X 10 mL) in T H F (70 mL) was added freshly distilled cyclopentadiene (1.32 g, 20.0 mmol) at room (64),124 (loo), 109 (67), 55 (75);HRMS calculated for Cl5HZO5P, 316.1439, found, 316.1441; 'H NMR (200 MHz, CDC1,) 6 3.80 (d, temperature. Gas vigorously evolved for about 2 min. After this J = 11.2 Hz, 3 H), 3.79 (d, J = 11.2 Hz, 3 H), 2.9-3.2 (m, 4 H), mixture had been stirred another 10 min, 21m (10.33 g, 21.9 mmol) 2.70 (dd, J = 19.0, 9.0 Hz, 1 H), 2.19 (br s, 1 H), 1.55-1.9 (m, 2 in THF (30 mL) was added quickly via cannula. More gas evolved H), 1.43 (m, 1 H), 1.23 (m, 1H), 1.00 (s, 3 H), 0.93 (s, 3 H), 0.91 and the reaction solution which had turned brown stirred at room (s, 3 H); 13CNMR (63.1 MHz, CDC1,) 6 219.8, 199.7 (d, J = 7.0 temperature for 8 h followed by heating at reflux for 2 h. Aqueous Hz), 57.9, 52.6 (d, J = 7.0 Hz), 52.5 (d, J = 7.0 Hz), 46.0, 45.6, acidic (HC1) workup and subsequent flash chromatography (20% ether in pentane) yielded colorless crystalline 5 (1.20 g, 31.2%): 44.9, 40.9, 40.0 (d, J = 40.0 Hz), 30.6, 19.8, 19.1, 18.7, 9.0. mp 44.0-44.5 'C; IR (thin film) 2987,2933,2857,1615,1448,1380, ( 1R,6S,7R)- l,lO,lO-Trimethyltricyclo[ 5.2.1.02*6]dec-2-en1234,1139,1078,857 cm-'; MS, m/z (relative intensity) 192 (M', &one (19). Method A. To sodium hydride (0.660 g, 60%, 16.50 34), 177 (19), 134 (25), 117 (1001, 105 (681, 91 (51), 78 (45); 'H mmol) washed with pentane (3 X 5 mL) in THF (40 mL) was NMR (250 MHz, CDC13)6 6.32 (br s, 2 H), 3.77 (m, 2 H), 2.75-2.90 added at room temperature 18 (4.745 g, 15.00 mmol) in THF (10 (m, 4 H), 2.40-2.55 (m, 2 H), 1.48 (s, 6 H); 13C NMR (63.1 MHz, mL) via syringe under nitrogen. Gas evolution was quite vigorous CDC13) 6 133.6, 132.3, 110.2, 78.3, 43.0, 30.1, 27.1; [ . ] 2 6 ~ 113.1' for about 10 min as the solution turned red. After having been (c 0.275, 95% ethanol). Anal. Calcd for ClpH1602: C, 74.97; H, heated to reflux for 18 h, the reaction was quenced with excess 8.39. Found: C, 74.75; H, 8.36. saturated aqueous NaHSO, and the resulting product purified by flash chromatography (25% ethyl acetate in pentane) to afford { q q( lR,2R,5R)-5-Methyl-2-(2-phenyl-2-propyl)cyclohexpure 19 as a colorless oil (2.11g, 73.9%): IR (thin f h )2961, 1701, 1-yl]cyclopentadienyl)dicarbonylcobalt (23). A solution of 1608,1475,1391,1162,1137,842,810,702cm-'; MS, m/z (relative 3 (1.402 g, 5.00 mmol) in 1,2-dichloroethane (10 mL) and cyclointensity) 190 (M', 57), 175 (la), 147 (go), 133 (39), 119 (89), 105 hexene (10 mL) was degassed by three freeze-pump-thaw cycles (36), 91 (68), 77 (49), 69 (47), 55 (48); HRMS calculated for under high vacuum and added to C O ~ ( C O(1.394 ) ~ g, 4.00 mmol) C13H180,190.1358, found, 190.1353;'H NMR (250 MHz, CDCIS) in a round-bottom flask equipped with a reflux condenser, and 6 5.81 (d, J = 2.5 Hz, 1 H), 3.36 (br s, 1 H), 2.48 (dd, J = 16.6, the mixture was heated at reflux under nitrogen for 16 h. The 5.9 Hz, 1 H), 2.24 (dd, J = 16.6, 4.6 Hz, 1 H), 1.98 (br dd, J = solvent was removed under vacuum and the oil taken up in de4, 3.9 Hz, 1 H), 1.87 (m, 1 H), 1.68 (m, 1 H), 1.20 (m, 2 H), 1.19 gassed pentane. The product was purified by chromatography (s, 3 H), 1.02 (s, 6 H). Anal. Calcd for C13H18O: C, 82.06; H, 9.53. on activity 3 alumina under nitrogen with degassed solvents (pentane). A single red fraction was collected which afforded 23 Found: C, 82.24; H, 9.50. Method B. To dimethyl methylphosphonate (54.60 g, 440 as a red oil (1.255 g, 65.0%): IR (thin film) 2958,2903,2003,1944, mmol) in diglyme (600 mL, freshly distilled under vacuum from 1596, 1491, 1434, 1361, 1037, 796, 693 cm-'; MS, m / z (relative LiAlH,) at -78 'C was added butyllithium (314 mL, 1.40 M in intensity) 394 (M', O.l), 366 ( l ) , 338 (181, 119 (loo), 105 (6), 95 hexane, 440 mmol). After the solution had been stirred at -78 (8),91 (27),84 (lo),81 (11);HRMS calcd for C,H,Co02, 394.1343, 'C for 1.5 h, 16 (47.7 g, 200.0 mmol) in diglyme (50 mL) was added found, 394.1331; 'H NMR (300 MHz, C6D6)6 7.16 (m, 2 H), 7.03 via cannula. The reaction mixture was stirred for 2 h at -78 'C, (m, 3 H), 4.28 (br s, 3 H), 4.11 (br s, 1 H), 2.15 (br d, J = 10.5 Hz, 1 H), 1.85 (br dd, J = 11, 10.5 Hz, 1 H), 1.60 (m, 3 H), 1.28 warmed to room temperature, heated to distill off the hexane, (m, 2 H), 1.10 (s, 3 H), 1.05 (s, 3 H), 0.97 (d, J = 6.4 Hz, 3 H), and subsequently stirred for another 18 h. Aqueous acidic (HC1) 0.75-1.00 (m, 2 H); 13CNMR (75.5 MHz, CsD6, DEPT) 6 151.8 workup followed by flash chromatography of the resulting orange liquid (30% ethyl acetate in pentane) gave a 1:lepimeric mixture (quat), 128.1 (CH), 126.0 (CH), 125.0 (CH), 118.9 (quat), 85.5 (CH), of 19 as a clear oil (19.47 g, 51.2%),used as such in the subsequent 83.3 (CH),83.0 (CH), 80.6 (CH),53.2 (CH), 51.6 (CH2),41.0 (quat), step. 38.8 (CH), 35.6 (CH,), 33.6 (CH), 29.2 (CHp), 28.1 (CH3), 25.9 (1R,7S)-1,10,10-Trimethyltricycl0[5.2.1.0~~~]deca-2,5-diene (CH3), 22.3 (CH3). Bis(q5-[(1R,2R ,5R)-5-methyl-2-(2-phenyl-2-propyl)cyclo(4) and (1R ,4S ,7R)-l,lO,lO-Trimethyltricyclo[5.2.1.02!6]dec2-en-4-01 (20). To LiAlH4 (0.190 g, 5.00 mmol) in ether (20 mL) hex-1-yl]cyclopentadienyl)dichlorotitanium (24). To 3 (1.402 was added 19 (0.951 g, 5.00 mmol) in ether (5 mL) dropwise under g, 5.00 mmol) in T H F (20 mL) at 0 'C was added butyllithium (3.44 mL, 1.6 M in hexane, 5.50 mmol) via syringe under nitrogen. nitrogen. The reaction mixture was stirred 30 min at room After 30 min, TiC1, (0.424 g, 2.75 mmol), slurried in THF (5 mL), temperature, water added dropwise to quench the excess hydride, and then aqueous 1N HCl added to neutralize the solution. The was added to the reaction solution, to be subsequently heated layen were separated and the aqueous portion extracted with ether at reflux for 4 h. Concentrated HCl (1mL) was added at -78 'C (3 X 10 mL). Benzene (50 mL) and 4-methylbenzenesulfonicacid and the solution allowed to warm to room temperature over 1 h. (0.019 g, 0.10 mmol) were added to the combined organic portions Dichloromethane (20 mL) was added, and the mixture was ex-
890 Organometallics, Vol. 7, No. 4,1988
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tracted with water (2 x 4 mL) and with saturated aqueous CaC1, (1 X 4 mL) to give a red crystalline mass that was recrystallized from dichloromethane-ether to result in 24 as red crystals (0.772 g, 45.6%): mp 283-284 OC; IR (neat) 2978,1601,1496,1443,1376, 1264, 1110, 735 cm-'; MS, m / z (relative intensity) 676 (M', 0.3), 641 (5), 570 (2), 397 (5), 362 (7), 280 (22), 161 (22), 141 (lo), 119 (loo), 115 (13), 105 (57), 91 (87), 79 (53); 'H NMR (300 MHz, CDCl,) 6 6.90-7.05 (m, 5 H), 6.20 (br s, 1 H), 6.10 (br s, 1 H), 6.03 (br s, 1 H), 5.58 (br s, 1 H), 2.65 (br dd, J = 10, 10 Hz, 1 H), 1.68-1.92 (m, 3 H), 1.18-1.43 (m, 3 H), 1.13 (s, 3 H), 1.07 (s, 3 H), 0.82-1.05 (m, 2 H), 0.81 (d, J = 6.2 Hz, 3 H); 13CNMR (75.5 MHz, CDCl,, DEPT) 6 151.2 (quat), 145.3 (quat), 127.6 (CH, 2 C), 127.1 (CH), 125.5 (CH, 2 C), 124.6 (CH), 123.1 (CH), 115.4 (CH), 108.9 (CH), 53.9 (CH), 43.7 (CH,), 41.7 (CH), 40.6 (CH,), 35.6 (CH,), 32.2 (CH), 30.3 (quat), 28.7 (CH,), 23.4 (CH,), 22.4 (CH,). Anal. Calcd for C4,H5,C12Ti: C, 74.44; H, 8.03; C1, 10.46. Found: C, 74.37; H, 8.00; C1, 10.27. Bis(q5-(1R,7S)-1,10,10-trimethyltricyclo[5.2.l.O2~6]dec-3,5dien-2-y1)dichlorotitanium(26a). Into a solution of 4 (1.743 g, 10.00 "01) in THF (15 mL) at 0 "C was injected butyllithium (7.86 mL, 1.4 M in hexane, 11.0 mmol) via syringe under nitrogen. After the solution had been stirred for 30 min, TiC13 (0.848 g, 5.5 mmol), slurried in THF (8 mL), was introduced into the reaction solution, to be heated at reflux for 4 h. After the solution had been cooled to 0 "C, concentrated HCl(1 mL) was added and the solution turned red as it was stirred for 10 min at 0 "C. Dichloromethane (20 mL) was added at room temperature, and the mixture was extracted with water (2 X 5 mL) and saturated aqueous CaC12 (1 X 5 mL) to give a thick red oil which crystallized in dichloromethane with added pentane to yield red crystals, mp 174-177 OC (0.448 g, 19.2%). 'H NMR analysis of these crystals gave evidence of a 955 mixture of two isomers. Recrystallization by slow evaporation of a dichloromethane-isooctane solution gave deep red crystals of 26a (0.258 g, 11.1%): mp 178-179 "C; IR (neat) 2958,1481,1455,1391,1374,1080,918,771 cm-'; MS, m / z (relative intensity) 429 (M' - C1,65), 394 (loo), 347 (12), 293 (261, 290 ( 4 3 , 256 (4), 173 (5); 'H NMR (250 MHz, CDCl,) 6 6.47 (d, J = 2.7 Hz, 2 H), 5.92 (dd, J = 2.7, 2.7 Hz, 1 H), 2.75 (d, J = 4.1 Hz, 1 H), 1.4-2.0 (m, 4 H), 1.23 (s, 3 H), 0.92 (s, 3 H), 0.27 (9, 3 H); I3C NMR (50.8 MHz, CDCI,) 6 158.5, 152.2,122.1,113.5, 113.0, 70.0, 54.2, 51.5, 32.2, 25.4, 21.0, 19.9, 12.8. Anal. Calcd for C2,H,,C12Ti: C, 67.10; H, 7.36; C1, 15.23. Found: C, 66.87; H, 7.38; C1, 15.48. 'H NMR analysis indicated that the isomeric purity of 26a was at least 98%. The minor isomer, which was not purified, was assigned structure 27 because of the presence of six singlets in the methyl region of the 'H NMR (250 MHz, CDC1,) spectrum of crude material: 6 1.41, 1.25, 1.13,0.93, 0.91, 0.85. (q5-(1R,7S)-1,10,10-Trimethyltricyclo[ 5.2.1.02s6]deca-3,5dien-2-y1)dicarbonylcobalt(25). A solution of 4 (0.261 g, 1.50 mmol) in a mixture of 1,2-dichloroethane and 1-pentene (15 mL, 2:l) was degassed by three freeze-pump-thaw cycles and then added to C O ~ ( C O(0.283 ) ~ g, 0.82 mmol). After the mixture had been heated at reflux under nitrogen for 40 h, a thick oil was obtained and purified by chromatography on activity 3 alumina (hexanes) under nitrogen to give 25 (3:l mixture of diastereomers) as a red oil (0.240 g, 55.5%): IR (thin film) 2962, 2011, 1955, 1619, 1453 cm-'; MS, m / z (relative intensity) 288 (M', 12), 260 (22), 232 (32), 188 (35), 159 (13), 131 (26), 129 (24), 115 (21); HRMS calcd for C15H17Co02, 288.0560, found, 288.0551; 'H NMR (200 MHz, C,D,) for major isomer, 6 4.55 (br d, J = 2.1 Hz, 1H), 4.50 (br d, J = 2.2 Hz, 1 H), 3.98 (dd, J = 2.2, 2.1 Hz, 1H), 1.40-2.10 (m, 5 H), 0.86 (s,3 H), 0.67 (s, 3 H), 0.42 (s, 3 H), for minor isomer, 6 4.54 (m, 1 H), 4.10 (m, 2 H), 1.40-2.25 (m, 5 H), 1.02 (s, 3 H), 0.65 (s, 3 H), 0.33 (s, 3 H). Alternatively, 4 (0.523 g, 3.00 mmol) was deprotonated with butyllithium (1.94 mL, 1.55 M, 3.00 mmol) at 0 "C and then exposed to ICo(CO), [generated by combining Co2(CO)~ (0.513 g, 1.50 mmol) and I2 (0.380 g, 1.50 mmol) in hexane (0 "C, 1 h)]. After 16 h a t room temperature, chromatography on activity 3 alumina (hexanes) under nitrogen afforded 25 (3:l mixture of diastereomers) as a red oil (0.412g, 47.6%). Attempted separation by reverse phase HPLC (two ODS 10 mm X 25 cm columns, 20% CH2C12in CH3CN) was unsuccessful. {q5-(3S, 4 5 )-3,4-(Dimethylmethylenedioxy) bicycle[ 4.3.01nona-6,8-dien-l-yl]dicarbonylcobalt (28). A solution of 5 (0.577
Halterman and Vollhardt g, 3.0 mmol) in dichloromethane (10 mL) and 1-pentene (5 mL) was degassed by three freeze-pump-thaw cycles, added to Coz(CO), (0.855 g, 2.5 mmol) in a round-bottom flask equipped with a reflux condenser, and heated at reflux under nitrogen for 30 h, the solvent removed under vacuum, and the oil taken up in degassed pentane. The product was purified by activity 3 alumina chromatography under nitrogen with degassed solvents (20% ether in pentane). A single red fraction was collected which crystallized upon removal of the solvent under vacuum to provide 28 (0.394 g, 42.9%): mp 72-73 OC; IR (neat) 2989,2928,2859,2024,1960, 1449, 1381,1236,1142,1087,857cm-'; MS, m / z (relativeintensity) 306 (M', 36), 278 (7), 250 (71), 208 (38), 192 (28), 164 (691, 162 (61), 138 (31), 115 (35), 105 (35), 91 (32), 59 (49); HRMS calcd for C14H15Co04, 306.0302, found, 306.0291; 'H NMR (300 MHz, C6D6)6 4.43 (dd, J = 2.6, 2.5 Hz, 1H), 4.31 (m, 2 H), 4.08 (ddd, J = 10.5, 9.2, 5.1 Hz, 1 H), 3.32 (ddd, J = 10.3, 9.2, 7.0 Hz, 1H), 2.65 (dd, J = 14.6, 5.1 Hz, 1 H), 2.54 (AB m, 2 H), 2.11 (dd, J = 14.6, 10.5 Hz, 1 H), 1.42 (a, 3 H), 1.40 (s, 3 H); 13C NMR (75.5 MHz, c&, off-reson decoup) 6 206 (br s), 110.9 (s), 101.2 (s), 99.3 (s), 83.2 (d), 82.1 (d), 81.4 (d), 78.5 (d), 77.6 (d), 28.7 (t), 28.1 (t), 27.3 (q), 27.2 (q); [a]26D 70" (c 0.00095, 95% ethanol). A Typical Asymmetric Hydrogenation Catalyzed by 24. A solution of 2-phenyl-1-butene (30) (0.529 g, 4.00 mmol) and 24 (0.034 g, 0.05 mmol) in toluene (4 mL) was degassed by three freeze-pump-thaw cycles. The solution was placed under 1 atm of hydrogen and was stirred for 10 min at 20 "C. Butyllithium (0.090 mL, 1.62 M, 0.146 mmol) was added at room temperature causing the solution to turn dark slowly over 1 h. The uptake of hydrogen was slow, yet steady, until the reaction was complete after 40 h. Aqueous workup and distillation provided 2phenylbutane (31) quantitatively as a clear liquid. The optical rotation of a sample purified by preparative GC indicated a 33% ee: [ a ] 2 6 7.33" D (c 0.104, ethanol). An analogous procedure was adopted for the asymmetric hydrogenations catalyzed by 26a. l-(Trimethylsilyl)-1,7-nonadiyne[32, R' = Si(CH3),, R2 = CH3]. Butyllithium (1.50 mL, 1.80 M in hexane, 2.70 mmol) was added at -78 "C to a solution of l-(trimethylsilyl)-l,7-octadiyne~ (0.500 g, 2.60 mmol) in THF (10 mL). The solution was allowed to warm to 0 "C over 20 min and cooled to -78 "C and iodomethane (0.730 g, 5.14 mmol) added. After the mixture had been left standing at room temperature overnight, aqueous workup followed by Kugelrohr distillation yielded a colorless liquid (0.47 g, 87.8%): IR (thin film) 2956,2179,1448,1332,1252,1019,850, 763,701 cm-'; MS, m/z (relative intensity) 192 (M', 0.4), 177 (16), 135 (7), 117 (15), 109 (7), 97 (13), 83 (12), 73 (loo), 59 (43); 'H NMR (300 MHz, CDCl,) 6 2.20 (t, J = 6.8 Hz, 2 H), 2.11 (m, 2 H), 1.74 (t,J = 2.5 Hz, 3 H), 1.55 (m, 4 H), 0.13 (s, 9 H); 13CNMR (75.5 MHz, CDClJ 6 107.1, 84.5, 78.7, 75.6, 28.1, 27.7, 19.4, 18.2, 3.4, 0.1. Anal. Calcd for C12H20Si:C, 74.92; H, 10.48. Found: C, 74.74; H, 10.32. l-(Trimethylsilyl)-1,7-decadiyne[32, R' = Si(CH,),, R2 = CH3CH2]. Butyllithium (2.75 mL, 1.60 M in hexane, 4.40 mmol) was added dropwise at -78 OC to a solution of 1,7-decadiyne(0.537 g, 4.00 mmol) in THF (10 mL). The solution was allowed to warm to 0 "C over 20 min and then cooled to -78 OC and chlorotrimethylsilane (0.869 g, 8.00 mmol) added. After the mixture had been left standing at room temperature overnight, aqueous workup and Kugelrohr distillation afforded a colorless liquid (0.809 g, 97.9%): IR (thin film) 2960, 2178, 1463, 1328, 1252, 1023, 844, 762,700 cm-'; MS, m / z (relative intensity) 206 (M', l), 191 (lo), 163 (8), 132 (16), 83 (12), 73 (loo), 59 (54); 'H NMR (300 MHz, CDCl,) 6 2.21 (t,J = 6.8 Hz, 2 H), 2.14 (m, 4 H), 1.57 (m, 4 H), 1.11 ( ~ , J = ~ . ~ H ~ , ~ H ) , ~ . ~ ~ ( S , ~ H ) ; ' ~ C N ~ V I R 6 107.2, 84.5,81.9, 79.0, 28.2, 27.7, 19.4, 18.3, 14.3, 12.4,0.2. Anal. Calcd for C13H2,Si: C, 75.65; H, 10.75. Found: C, 75.87; H, 10.67. Complexed Cyclopentadienones 33 [R' = Si(CH3)3,R2 = HI Derived from 23. A solution of 23 (0.287 g, 0.74 mmol) and 32 [R' = Si(CH,),, R2 = HI (0.178g, 1.00 mmol) in THF (50 mL) was irradiated for 6 h with a medium-pressure 450-W Hanovia mercury vapor lamp while being cooled by both a -20 "C bath circulating between the lamp and the reaction solution and a -30 "C external bath. The resulting red oil was purified by flash chromatography. Elution with ether removed excess diyne and the arene byproducts. Elution with 20% methanol in ether gave a red fraction whose 'H NMR analysis showed a diastereomeric
Synthesis of Cyclopentadienylmetal Complexes mixture of products (0.217 g, 53.9%, ratio 52:48). These compounds were separable by flash chromatography with 10% methanol in ether to yield first the minor isomer (0.100 g) as a red oil: IR (thin film) 2958, 1597, 1251, 847,768, 704 cm-'; MS, m/z (relative intensity) 544 (M', 31), 471 (8), 425 (43), 338 (58), 214 (15), 205 ( E ) , 119 ( E ) , 111 (27), 97 (42), 91 (13), 83 (42), 73 (16), 71 (59), 57 (100); HRMS calcd for C,,H,,CoOSi, 544.2571, found, 544.2578; 'H NMR (300 MHz, C&) 6 7.08 (m, 2 H), 6.99 (m, 3 H), 4.87 (br s, 1 H), 4.18 (br s, 1 H), 4.01 (8, 1 H), 3.83 (br s, 1 H), 3.64 (br s, 1 H), 2.84 (br d, J = 12.6 Hz, 1 H), 2.40-2.79 (m, 2 H), 2.05-2.30 (m, 3 H), 1.95 (m, 1 H), 1.45-1.90 (m, 7 H), 1.30-1.40 (m, 2 H), 1.26 (d, J = 6.4 Hz, 3 H), 1.15 (m, 1H), 1.08 ( 8 , 3 H), 1.02 (s, 3 H), 0.47 ( 8 , 9 H); 13C NMR (75.5 MHz, C&) 6 166.2, 151.7, 128.2, 125.9, 125.0, 111.3,96.6,94.3, 81.1, 80.5, 79.4, 79.2, 64.2,62.5, 54.6, 44.2,40.8, 40.4, 36.1, 33.7, 29.6, 28.8, 28.7, 25.3, 24.2, 23.4, 22.9, 22.2,0.3. Anal. Calcd for C3,H4,CoOSi: C, 72.76; H, 8.33. Found: C, 72.98; H, 8.52. The subsequent major isomer (0.109 g) was also obtained as a red oil: IR (thin film) 2961, 1597, 1450, 1374, 1251, 848, 768, 705 cm-'; MS, m/z (relative intensity) 544 (M', 51), 471 (16), 425 (85), 338 (loo), 214 (29), 203 (14), 119 (14), 97 (15), 83 (17), 71 (23), 57 (35); HRMS calcd for C3,H4,CoOSi, 544.2571, found, 544.2573; 'H NMR (300 MHz, C6D6) 6 7.07 (m, 2 H), 6.99 (m, 3 H), 4.82 (br s, 1 H), 4.08 (s, 1 H), 3.98 (br s, 1 H), 3.73 (br s, 1 H), 3.50 (br s, 1H), 2.90 (br dd, J = 12.8, 2.2 Hz, 1H), 2.45 (ddd, J = 12.8, 12.5, 2.7 Hz, 1 H), 1.98-2.23 (m, 2 H), 1.78-1.95 (m, 2 H), 1.71 (m, 3 H), 1.40-1.70 (m, 5 H), 1.27-1.38 (m, 2 H), 1.22 (d, J = 6.4 Hz, 3 H), 1.10 (m, 1 H), 1.09 (s, 3 H), 1.03 (s, 3 H), 0.47 (s, 9 H); l3C NMR (75.5 MHz, C&) 6 166.3, 152.0, 128.1, 126.0, 124.8, 111.3,96.5,94.2,82.7,80.7,78.2,78.0, 62.9, 62.8,54.1, 44.3, 40.8, 39.5, 36.1, 33.5, 29.4, 29.1, 25.4, 25.0, 24.3, 23.4, 22.9, 22.4,0.2. Anal. Calcd for CsH,CoOSi: C, 72.76; H, 8.33. Found C, 73.34; H, 8.41. Complexed Cyclopentadienones 33 [R'= Si(CH3),, R2 = CHJ Derived from 23. A solution of 23 (0.065 g, 0.17 mmol) and 32 [R' = Si(CH3),, R2 = CH,] (0.047 g, 0.22 mmol) in T H F (50 mL) was treated as described above to give a diastereomeric mixture of products as a red oil (0.060 g, 63.8%, ratio 67:33). Separation by flash chromatography (5% methanol in ether) produced a minor isomer first (0.018 g) as a red oil: IR (thin film) 2958, 1594, 1448, 1249, 853, 767, 705 cm-'; MS, m / z (relative intensity) 558 (M', 96), 485 ( E ) , 439 (58), 338 (1001, 214 (30), 203 (13), 138 (lo), 124 ( l l ) , 119 (17), 57 (14); HRMS calcd for CaH&o0Si, 558.2728, found 558.2734; 'H NMR (300 MHz, c&) 6 6.95-7.15 (m, 5 H), 4.82 (br s, 1 H), 3.75 (br s, 1 H), 3.69 (br s, 1 H), 3.62 (br s, 1 H), 3.06 (br dd, J = 13.3, 2.3 Hz, 1 H), 2.26 (ddd, J = 9.9, 9.7, 2.2 Hz, 1H), 2.17 (ddd, J = 16.6, 7.3, 6.5 Hz, 1 H), 1.82-2.05 (m, 2 H), 1.72-1.82 (m, 4 H), 1.69 (m, 1 H), 1.5G1.62 (m, 3 H), 1.45 (s,3 H), 1.36 (d, J = 6.4 Hz, 3 H), 1.30-1.40 (m, 3 H), 1.14 (m, 1 H), 1.12 (s, 3 H), 1.06 (s, 3 H), 0.44 (s, 9 H); '% NMR (75.5 M H Z , c&) 6 166.2,151.9, 128.0,126.9,124.9, 110.1, 94.2, 93.4, 81.3, 81.2, 80.2, 78.0, 74.8, 61.1, 55.1, 42.6, 40.8, 40.1, 36.4, 34.2, 29.8, 28.4, 25.5, 25.2, 23.4, 22.9, 22.7, 22.1, 9.3, 0.3. The second fraction contained the major isomer (0.037 g), also as a red oil: IR (thin film) 2960,1594,1451,1248,853,839,767, 707 cm-'; MS, m / z (relative intensity) 558 (M', loo), 485 (13), 439 (50), 338 (76), 214 (19), 119 (19), 109 (27), 105 (13), 83 (39), 71 (48.3), 57 (81); HRMS calcd for CaH,CoOSi, 558.2728, found 558.2732; 'H NMR (300 MHz, C6D6) 6 6.95-7.15 (m, 5 H), 4.60 (br s, 1H), 3.83 (br s, 1H), 3.44 (br s, 2 H), 3.18 (br dd, J = 12.9, 2.3 Hz, 1 H), 2.55 (ddd, J = 9.9, 9.7, 2.4 Hz, 1 H), 2.18 (ddd, J = 16.8, 7.2, 6.5 Hz, 1H), 1.80-2.00 (m, 3 H), 1.60-1.80 (m, 5 H), 1.52 (m, 2 H), 1.49 (9, 3 H), 1.35 (d, J = 6.4 Hz, 3 H), 1.30 (m, 3 H), 1.13 (m, 1 H), 1.12 (s, 3 H), 1.07 (s, 3 H), 0.48 (s, 9 H); 13C NMR (75.5 MHz, C6D6) 6 166.0, 152.1, 128.3, 126.0, 124.8, 109.4, 94.1,93.7,81.6, 81.0, 80.4, 79.0, 76.1, 60.0, 54.8, 42.3, 40.7, 40.4, 36.3, 33.8, 29.6, 28.5, 25.6, 25.3, 23.3, 23.2, 22.7, 22.1, 9.9, 0.2. Complexed Cyclopentadienones 33 [R' = Si(CH,),, R2 = CH,CH,] Derived from 23. A solution of 23 (0.090 g, 0.23 "01) and 32 [R' = Si(CH,),, R2 = CH3CH2](0.062 g, 0.30 mmol) in T H F (50 mL) was treated as described above to provide a diastereomeric mixture of products as a red oil (0.097 g, 73.6%, ratio 60:40). Separation by flash chromatography (5% methanol in ether) gave first the minor component (0.033 g) as a red oil: IR (thin film) 2958, 1588, 1448, 1249, 839, 741, 703 cm-'; MS, m / z (rekative intensity) 572 (M', 68), 557 (3), 499 (13), 453 (37), 338
Organometallics, Vol. 7, No. 4, 1988 891 (60), 216 (13), 214 (18), 119 ( 7 ) , 57 (13), 43 (100) HRMS calcd for CSH,CoOSi, 572.2885, found, 572.2885; 'H NMR (300 MHz, C6D6)6 6.97-7.14 (m, 5 H), 4.58 (br d, J = 1.7 Hz, 1H), 4.04 (br d, J = 1.7 Hz, 1 H), 3.44 (br s, 2 H), 3.18 (br d, J = 12.6 Hz, 1 H), 2.60 (m, 2 H), 2.21 (m, 1 H), 1.85-2.05 (m, 3 H), 1.70 (m, 6 H), 1.55 (m, 3 H), 1.42 (m, 1 H), 1.34 (d, J = 6.4 Hz, 3 H), 1.18 (m, 1 H), 1.12 (s, 3 H), 1.11(m, 4 H), 1.07 (s, 3 H), 0.48 (s, 9 H); '9NMR (75.5 MHz, C a d 6 165.8,152.1,127.9,126.0,124.8,109.5, 93.9, 93.7, 81.0, 80.9, 80.4, 80.3, 79.9, 54.9, 42.2, 40.7, 40.5, 36.3, And. 33.8, 29.7, 28.4,25.6,25.3,23.5, 23.3,22.8,22.1,18.8,13.0,0.2. Calcd for C3,H4&oOSi: C, 73.39; H, 8.62. Found: C, 74.51; H, 8.63. The second fraction contained the major isomer (0.053 g) as a red oil: IR (thin film) 2959,1590,1448,1250,838,767,738,703 cm-'; MS, m / z (relative intensity) 572 (M', 12), 499 (2), 453 (9), 338 (16), 214 (4), 179 (6), 71 (13), 57 (24), 43 (100); HRMS calcd for C35H49CoOSi, 572.2885, found, 572.2882; 'H NMR (300 MHz, C,&) 6 6.95-7.15 (m, 5 H), 4.82 (br 8 , 1 H), 3.76 (br 9, 1 H), 3.72 (br s, 1 H), 3.63 (br s, 1 H), 3.06 (br d, J = 13.5 Hz, 1 H), 2.43 (m, 1 H), 2.34 (br dd, J = 10.3, 10.3 Hz, 1 H), 2.17 (m, 1 H), 1.85-2.10 (m, 3 H), 1.65-1.85 (m, 6 H), 1.36 (m, 1H), 1.34 (d, J = 6.4 Hz, 3 H), 1.17 (m, 5 H), 1.13 (s, 3 H), 1.08 (s, 3 H), 0.43 (s, 9 H); 13CNMR (75.5MHz, C6Ds)6 165.8,151.9,128.0,125.9,124.9, 110.0, 94.5, 93.0, 81.2, 80.9, 80.2, 79.9, 78.5, 65.9, 55.2, 42.4, 40.8, 40.4, 36.3, 34.0, 29.8, 28.5, 25.5, 25.2, 23.3, 23.0, 22.7, 22.1, 18.5, 13.0, 0.4. Complexed Cyclopentadienones 33 [R' = CH,, R2 = H ) Derived from 23. A solution of 23 (0.076 g, 0.20 mmol) and 32 (R' = CH,, R2 = H) (0.096 g, 0.80 mmol) in T H F (50 mL) was treated as described above to furnish an inseparable diastereomeric mixture of products as a red oil (0.052 g, 53.5%, ratio 61:39): IR (thin film) 2958,1483,1449,1268,1033,808,705 cm-'; MS, m / z (relative intensity) 486 (M', 71), 471 (6), 367 (loo), 338 (92), 216 (15), 214 (26), 177 (ll),151 (12), 138 (lo), 119 (29), 105 (13), 91 (26),69 (22),57 (39); HRMS calcd for C,,H,CoO, 486.2332, found, 486.2338; 'H NMR (300 MHz, C6D6)for major isomer, 6 6.97-7.12 (m, 5 H), 4.39 (br s, 1 H), 4.23 (br s, 1 H), 4.21 (s, 1 H), 3.88 (br s, 1 H), 3.57 (br s, 1 H), 2.70 (m, 1 H), 2.25 (m, 2 H), 1.90-2.10 (m, 2 H), 1.70 (m, 5 H), 1.63 (s, 3 H), 1.50 (m, 3 H), 1.30 (m, 3 H), 1.26 (d, J = 6.4 Hz, 3 H), 1.15 (m, 1 H), 1.10 (s, 3 H), 1.02 (s, 3 H), for minor isomer, 6 6.97-7.12 (m, 5 H), 4.53 (br s, 1 H), 4.21 (s, 1 H), 3.98 (br s, 1 H), 3.72 (br s, 1 H), 3.55 (br s, 1 H), 2.70 (m, 1 H), 2.39 (m, 1 H), 2.25 (m, 1 H), 1.90-2.10 (m, 2 H), 1.70 (m, 5 H), 1.65 (s, 3 H), 1.50 (m, 3 H), 1.30 (m, 3 H), 1.19 (d, J = 6.4 Hz, 3 H), 1.17 (s, 3 H), 1.15 (m, 1 H), 1.08 (s, 3 H); 13C N M R (75.5 MHz, c&) 6 157.7 (br),152.0,151.8,128, 126.0,125.9, 124.9, 124.8, 111.5, 110.3, 91.3, 89.1, 85.9, 83.0, 81.9, 81.8, 81.7, 80.6, 80.5, 78.9, 78.3, 61.4, 60.7, 60.6, 53.9, 50.1, 45.8, 44.6, 40.9, 40.8, 39.3, 38.6, 36.0, 35.9, 33.6, 33.3, 29.5, 29.3, 28.9, 28.4, 25.4, 24.9, 23.7, 23.5, 23.1, 22.9, 22.6, 22.5, 22.4, 22.3, 22.1, 9.7, 9.6. Complexed Cyclopentadienones 33 (R' = CH3CH2,R2 = H ) Derived from 23. A solution of 23 (0.182 g, 0.47 mmol) and 39 (0.080 g, 0.60 mmol) in THF (50 mL) was treated as described above to give an inseparable diastereomeric mixture of products as a red oil (0.059 g, 54%, ratio 56:44): IR (thin film) 2954,1602, 1455, 819, 768, 707 cm-'; MS, m / z (relative intensity) 500 (M', 55), 471 (lo), 381 (loo), 353 (13), 338 (80), 214 (27), 203 (14), 177 (12), 167 (lo), 137 (13), 119 (20), 105 (14), 91 (24), 83 (22), 71 (32), 57 (60); HRMS calcd for C32H41C00,500.2489,found, 500.2488; 'H NMR (300 MHz, C6D6)for major isomer, 6 6.95-7.12 (m, 5 H), 4.48 (br s, 1 H), 4.07 (s, 1 H), 4.01 (br s, 1 H), 3.70 (br s, 1 H), 3.56 (br s, 1 H), 2.55-2.8? (m, 2 H), 2.31 (m, 1 H), 1.95-2.25 (m, 2 H), 1.45-1.90 (m, 10 H), 1.35 (m, 2 H), 1.18 (m, 7 H), 1.08 (s, 3 H), 1.05 (m, 1H), 101 (s, 3 H), for minor isomer, 6 6.95-7.12 (m, 5 H), 4.48 (br s, 1 H), 4.11 (br s, 1 H), 4.05 (s, 1 H), 3.87 (br s, 1 H), 3.57 (br s, 1H), 2.55-2.82 (m, 2 H), 1.95-2.25 (m, 3 H), 1.45-1.90 (m, 10 H), 1.35 (m, 2 H), 1.18 (m, 7 H), 1.08 (s, 3 H), 1.05 (m, 1 H), 0.98 (8,3 H); 13CNMR (75.5 MHz, CsD6) 6 159.2, 159.1, 152.0, 151.8, 127.9, 126.0, 125.9, 124.9, 124.8, 111.2, 110.2, 90.9, 89.3, 89.2, 84.9, 81.8, 81.4, 81.3, 81.2, 80.5, 80.3, 79.4, 79.0, 78.1, 61.1, 60.4, 54.1, 53.9, 50.0, 45.2, 44.4, 40.8,40.0, 39.0, 36.0, 35.9, 33.6, 33.4, 29.5, 29.4, 28.6, 28.2, 25.5, 25.1, 23.8, 23.6, 23.1, 23.0, 22.9, 22.7, 22.6, 22.5, 22.3, 18.7, 18.6, 13.3, 13.2. Complexed Cyclopentadienones 33 [R' = Si(CH3), R2 = CH,CH,] Derived from 28. A solution of 28 (0.061 g, 0.20 mmol) and 32 [R' = Si(CH,),, R2 = CH,CH2] (0.070 g, 0.27 mmol) in
Organometallics 1988,7, 892-898
892
THF was treated as described above to give an inseparable diastereomeric mixture of products as a red oil (0.075g, 69.4%,ratio 5050): IR (thin film) 2993,1649,1545,1449,1242,1083,850 em-'; MS, m / z (relative intensity) 470 (M', 12),455 (7),412 (loo), 395 (21),384 (15),339 (531,311(21);'H NMR (300MHz, C&) 6 4.44 (br s, 2 H), 4.25(m, 1H), 4.22(m, 1 H), 4.00(br s, 1 H), 3.81(br s, 1 H), 3.50 (br s, 2 H), 3.45(m, 2 H), 3.16(dd, J = 14.5,5.0 Hz, 1 H), 2.98(dd, J = 14.0,13.0Hz, 1 H), 2.63(dd, J = 14.5,5.0Hz, 1 H), 2.47 (m, 3 H), 2.29 (dd, J = 14.5,12.0Hz, 1 H), 2.12 (m, 5 H), 1.85(m, 8H),1.74(s, 3 H),1.68(s, 3 H), 1.61(m, 4 H), 1.51 (br s, 6 H), 1.38(s, 3 H),1.34(s, 3 H), 0.42(8,9 H), 0.38(s, 3 H); 95.5,95.3, 13CNMR (75.5MHz, C6D6)6 111.2,111.1,104.3,96.5,
94.9,94.2,81.8,81.6,79.3,78.7,78.6,78.4,78.2,78.1,76.9,76.8, 30.1,27.6,27.5,27.3,27.0,26.5,25.1,24.8,24.7,24.6,23.4,23.3, 22.8,22.6,22.5,22.2,15.8,7.6,6.9,0.3,0.2. Diene Complexes 35. A solution of 23 (0.153g, 0.62mmol) in toluene (5 mL) was degassed by three freezepumpthaw cycles and then added under nitrogen to 34 (0.215g, 0.56mmol) in a 15-mLround-bottom flask equipped with a reflux condenser. The mixture was heated at reflux and irradiated by a projector lamp (GE-ENH 250 W) for 10 h. The solvent was removed under vacuum and the residue filtered through activity 3 alumina with pentane to provide an inseparable mixture of two isomers of 35 (0.285g, 87.3%, ratio 5842)as a red oil (0.143g, 69.4%): IR (thin cm-'; MS, m / z (relative film) 2961,1604,1501,1452,1253,838,707 intensity) 584 (M', 9),511 (6),369 (17),338 (29),280 (a), 229 (13),
214 (3),169 (a), 119 (25),105 (lo), 97 (17),83 (20),71 (30),57 (100); HRMS calcd for C37H63C~Si, 584.3248,found, 584.3266; 'H NMR (300MHz, C&,) for major isomer, 6 7.05-7.23(m, 5 H), 4.87(br s, 1 H), 3.86 (br s, 1 H), 3.61 (br s, 2 H), 2.78(m, 1 H), 2.40-2.52(m, 2 H), 2.33 (m, 3 H), 1.87-2.18(m, 4 H), 1.40-1.85 (m, 12 H),1.31(8, 3 H), 1.11(d, J = 6.1Hz, 3 H), 1.10(s, 3 H), 0.85-1.0(m, 2 H),0.40-0.55 (m, 2 H), 0.29 ( 8 , 9 H), for minor isomer, 6 7.05-7.23(m, 5 H), 4.29(br s, 1 H), 4.27(br s, 1 H), 4.08 (br s, 1 H), 3.97(br s, 1 H), 2.97(m, 1 H), 2.40-2.52(m, 2 H), 2.33 (m, 3 H), 1.87-2.18(m, 4 H), 1.40-1.85(m, 12 H), 1.28 (s, 3 H), 1.07(d, J = 6.0Hz, 3 H), 1.03(s, 3 H), 0.85-1.0(m, 2 H), 0.40-0.55
(m, 2 H), 0.30(~,9 H); 13CNMR (75.5MHz, C&) 6 152.6,128.2,
125.9,125.1,125.0,111.9,108.7,93.9,87.4,83.0,81.2,80.1,79.4, 78.7,78.6,56.0,55.7,49.1,48.1,41.4,40.8,40.6,40.0,39.9,36.3, 36.1,36.0,35.9,34.8,34.1,34.0,33.8,33.7,32.9,30.5,30.4,29.9, 29.4,23.3,29.1,28.0,27.6,24.9,24.4,24.2,24.1,24.0,23.6,23.2, 22.9,22.5,22.3,0.8,0.7.
Acknowledgment. This work was supported by NIHGM22479. R.L.H. was t h e recipient of a University of California Regents' Fellowship (1982-1984). K.P.C.V. was a Miller Research Professor in residence (1985-1986). 4,59581-87-2; 5,106509-11-9; Registry No. 3,112505-23-4; 7,97371-54-5; 8,104870-75-9; 10,112505-24-5; 11,65253-04-5; 12, 112505-25-6; 13,112505-26-7; 14,112505-27-8; 15,464-49-3; 16, 106509-10-8; 17,106566-51-2; 18,112505-28-9; 19,112505-29-0; 20,112505-30-3; 21,37002-45-2; 22,112572-77-7; 23,112505-34-7; 24,112505-35-8; 25a,106564-05-0; 26a,106564-06-1; 27,11250533-6; 28,106563-88-6; 30,2039-93-2; 31,135-98-8; 32 (R' = Si(CH,),, R2 = H), 83182-85-8;32 (R' = Si(CH,),, R2 = CH,), 112505-31-4; 32 (R = Si(CH,),, R2 = CH2CH3),112505326;32 (R' = Me, R2 = H), 4116-92-1; 33 (R' = Si(CH,),, R2 = H, from 23),112505-38-1; 33 (R' = H, R2 = Si(CH,),, from 23),112572-79-9 33 (R' = Si(CH,),, R2 = CH,, from 23),112505-39-2; 33 (R' = CH,, 33 (R' = Si(CH,),, R2 = R2 = Si(CH,),, from 23), 112572-80-2; Et, from 23),112505-40-5; 33 (R = Et, R2 = Si(CH,),, from 23), 112572-81-3; 33 (R' = H, R2 = Me, from 23), 112505-41-6; 33 (R' = Me, R2 = H, from 23), 112572-82-4; 33 (R' = H, R2 = Et, from 23), 112505-42-7; 33 (R' = Et, R2 = H, from 23),112572-83-5; 33 (R' = Si(CH3),,R2 = Et, from 28),112572-85-7; 33 (R' = Et, R2 = Si(CH3),,from 28),112505-44-9; 34,74585-57-2; 35 (isomer l), 112505-43-8; 35 (isomer 2),112572-84-6; 1,7-decadiyne,63815-29-2; TiCl,, 7705-07-9; C O ~ ( C O 10210-68-1; )~, ICO(CO)~, 15976-97-3; cyclopentadiene, 542-92-7;(2R,4R)-4-methyl-2-(2-phenyl-2propyl)cyclohexanone, 104870-79-3; (lR,2R,5R)-5-methy1-2-(2phenyl-2-propyl)cyclohexanol,104870-80-6; cyclopentadienylsodium-dimethoxyethane, 62228-16-4.
Synthesis, Reactivity, and X-ray Crystal Structure of an Anionic, Mixed-Metal Ketenylidene Cluster: [PPN][ Fe,Co( CO),( CCO)] Stanton Ching," Elizabeth M. Holt,lb Joseph W. Kolis,'a-cand Duward F. Shriver"" Departments of Chemistry, Northwestern University, Evanston, Illinois 6020 1, and Oklahoma State Univem'ty, Stillwater, Oklahoma 74078 Received August 4, 1987
The anionic mixed-metal ketenylidene cluster [PPN] [Fe,Co(CO),(CCO)] (1) can be prepared in high ) ~ a CO yield by a facile metal substitution reaction between [PPN],[Fe (CO),(CCO)] and C O ~ ( C Ounder but its reactivity more closely resembles atmosphere. This cluster is structurally similar to [Fe3(CO)g(CCO)]3-, that of the cationic cluster [CO~(CO)~(CCO)]+. Compound 1 undergoes protonation a t the a-carbon atom to give Fe2Co(CO)lo(CH)but is inert to electrophilic attack by carbocationic reagents. Nucleophilic reagents such as LiCH,, NaOCH , and KBEt3H attack a t the &carbon atom to afford dinegatively charged species [F~,CO(CO),(CC(O)R)]~(R= CH3, OCH,, H). Compound 1 crystallizes in the space group C2/c with a = 27.231 (7)A, b = 17.670 (6) A, c = 23.072 (10)A, p = 126.54 (3)O,V = 8919.9(70) A3, and 2 = 8.
Introduction Ketenylidene ( c c o ) ligands on trinuclem metal clusters are known to undergo diverse chemistry with respect t o C-C bond cleavage,C-0 activation, C-C a n d C - 0 bond formation, a n d cluster b ~ i l d i n g . ~ - An ' ~ important factor (1) (a) Northwestern University. (b) Oklahoma State University. (c) Current address: Department of Chemistry, Clemson University, Clemson, SC 29631. (2) Seyferth, D.; Hallgren, J. E.; Eschbach, C. S. J. Am. Chem. SOC. 1974, 96, 1730.
in determining t h e reactivity of t h e CCO ligand is t h e charge on t h e cluster. Ketenylidene ligands on c a t i o n i ~ ~ - ~ (3) Seyferth, D.; Williams, G. H.; Nivert, C. L. Inorg. Chem. 1977, 16,
758.
(4) Mlekuz, M.; D'Agostino, M. F.; Kolis, J. W.; McGlinchey, M. J. J. Organomet. Chem. 1986, 303, 361. (5) Sievert, A. C.; Strickland, D. S.; Shapley, J. R.; Steinmetz, G. R.; Geoffroy, G. L. Organometallics 1982, 1, 214. (6) Shapley, J. R.; Strickland, D. S.; St. George, G. M.; Churchill, M. R.; Bueno, C. Organometallics 1983, 2, 185. (7) Holmgren, J. S.; Shapley, J. R. Organometallics 1984, 3, 1322.
0276-7333/88/2307-0892$01.50/00 1988 American Chemical Society
